Cannot assign value "<date>" of type "System.String" to property "" expecting type "System.DateTime".

[Matthew-Wise]

Running on all latest versions of Deploy (16.0.0) (with Contrib and Forms) and Umbraco (16.0.0) I pushed a single page to the developement environment, which was successful however on viewing the page I get the following

{
    "type": "Error",
    "title": "Cannot assign value \"18/04/2025 00:00:00 +01:00\" of type \"System.String\" to property \"dateStamp\" expecting type \"System.DateTime\".",
    "status": 500,
    "detail": "   at Umbraco.Cms.Core.Models.Property.ThrowTypeException(Object value, Type expected, String alias)\r\n   at Umbraco.Cms.Core.Models.Property.TryConvertAssignedValue(Object value, Boolean throwOnError, Object& converted)\r\n   at Umbraco.Cms.Core.Models.Property.SetValue(Object value, String culture, String segment)\r\n   at Umbraco.Cms.Core.PropertyEditors.BlockValuePropertyValueEditorBase`2.MapBlockItemDataToEditor(IProperty property, List`1 items, String culture, String segment)\r\n   at Umbraco.Cms.Core.PropertyEditors.BlockValuePropertyValueEditorBase`2.MapBlockValueToEditor(IProperty property, TValue blockValue, String culture, String segment)\r\n   at Umbraco.Cms.Core.PropertyEditors.BlockEditorPropertyValueEditor`2.ToEditor(IProperty property, String culture, String segment)\r\n   at Umbraco.Cms.Core.PropertyEditors.BlockValuePropertyValueEditorBase`2.MapBlockItemDataToEditor(IProperty property, List`1 items, String culture, String segment)\r\n   at Umbraco.Cms.Core.PropertyEditors.BlockValuePropertyValueEditorBase`2.MapBlockValueToEditor(IProperty property, TValue blockValue, String culture, String segment)\r\n   at Umbraco.Cms.Core.PropertyEditors.BlockEditorPropertyValueEditor`2.ToEditor(IProperty property, String culture, String segment)\r\n   at Umbraco.Cms.Api.Management.Mapping.Content.ContentMapDefinition`3.<>c__DisplayClass4_1.<MapValueViewModels>b__1(IPropertyValue propertyValue)\r\n   at System.Linq.Enumerable.ListSelectIterator`2.MoveNext()\r\n   at System.Linq.Enumerable.SelectManySingleSelectorIterator`2.MoveNext()\r\n   at System.Linq.Enumerable.IEnumerableWhereIterator`1.ToArray()\r\n   at Umbraco.Cms.Api.Management.Mapping.Content.ContentMapDefinition`3.MapValueViewModels(IEnumerable`1 properties, ValueViewModelMapping additionalPropertyMapping, Boolean published)\r\n   at Umbraco.Cms.Api.Management.Mapping.Document.DocumentMapDefinition.Map(IContent source, DocumentResponseModel target, MapperContext context)\r\n   at Umbraco.Cms.Core.Mapping.UmbracoMapper.Map[TTarget](Object source, Type sourceType, MapperContext context)\r\n   at Umbraco.Cms.Core.Mapping.UmbracoMapper.Map[TTarget](Object source)\r\n   at Umbraco.Cms.Api.Management.Factories.DocumentPresentationFactory.CreateResponseModelAsync(IContent content, ContentScheduleCollection schedule)\r\n   at Umbraco.Cms.Api.Management.Controllers.Document.ByKeyDocumentController.ByKey(CancellationToken cancellationToken, Guid id)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.TaskOfIActionResultExecutor.Execute(ActionContext actionContext, IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask`1 actionResultValueTask)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()\r\n--- End of stack trace from previous location ---\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|25_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()\r\n--- End of stack trace from previous location ---\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)\r\n   at Umbraco.Cms.Web.Common.Middleware.BasicAuthenticationMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)\r\n   at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.InterfaceMiddlewareBinder.<>c__DisplayClass2_0.<<CreateMiddleware>b__0>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n   at Umbraco.Cms.Api.Management.Middleware.BackOfficeExternalLoginProviderErrorMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)\r\n   at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.InterfaceMiddlewareBinder.<>c__DisplayClass2_0.<<CreateMiddleware>b__0>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n   at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)\r\n   at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)\r\n   at Umbraco.Cloud.Cms.PublicAccess.Middleware.CloudPublicAccessMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)\r\n   at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.InterfaceMiddlewareBinder.<>c__DisplayClass2_0.<<CreateMiddleware>b__0>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n   at Umbraco.Deploy.Infrastructure.Middleware.BearerTokenAuthenticationMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)\r\n   at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.InterfaceMiddlewareBinder.<>c__DisplayClass2_0.<<CreateMiddleware>b__0>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n   at Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)\r\n   at Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)\r\n   at Microsoft.AspNetCore.Localization.RequestLocalizationMiddleware.Invoke(HttpContext context)\r\n   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)\r\n   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)\r\n   at StackExchange.Profiling.MiniProfilerMiddleware.Invoke(HttpContext context) in C:\\projects\\dotnet\\src\\MiniProfiler.AspNetCore\\MiniProfilerMiddleware.cs:line 112\r\n   at Umbraco.Cms.Web.Common.Middleware.UmbracoRequestMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)\r\n   at Umbraco.Cms.Web.Common.Middleware.UmbracoRequestMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)\r\n   at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.InterfaceMiddlewareBinder.<>c__DisplayClass2_0.<<CreateMiddleware>b__0>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n   at Umbraco.Cms.Web.Common.Middleware.PreviewAuthenticationMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)\r\n   at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.InterfaceMiddlewareBinder.<>c__DisplayClass2_0.<<CreateMiddleware>b__0>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n   at Umbraco.Cms.Web.Common.Middleware.UmbracoRequestLoggingMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)\r\n   at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.InterfaceMiddlewareBinder.<>c__DisplayClass2_0.<<CreateMiddleware>b__0>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddlewareImpl.<Invoke>g__Awaited|10_0(ExceptionHandlerMiddlewareImpl middleware, HttpContext context, Task task)",
    "instance": "InvalidOperationException"
}

Bug summary

This Date Picker is on a block list item that is on a block within another block list. (main list -> child list -> date picker)

The date picker is configured as below and is not mandatory

Workaround Attempts

Tried both methods here without success - #209

[danielfalkmouritzen]

I have this problem too. Altho this is also a problem with just a date or datetime property in a block list, it doesnt need to be nested inside another block list for this error to happen.

Steps to reproduce the issue

Create a fresh Umbraco 16 project on Cloud.

There are 2 scenarios in which the error can occur.

Scenario 1:

Create document type (Home)
Create element type with a DatePicker With Time
Create a BlockList data type and allow the element type with the DatePicker With Time to be picked.
Add the BlockList as a property on the Home document type
Create content with it.
Clone your environment
Content restore
Your content will not be published, but saved.

If you save and publish, it might succeed, but in the error log, you will see the error.
If you save and publish again, it appears the operation will just run forever
​
​

Scenario 2:
Much like scenario 1, but in this case you start locally.

Clone your Cloud environment (empty in this case)
Create document type (Home)
Create element type with a DatePicker With Time
Create a BlockList data type and allow the element type with the DatePicker With Time to be picked.
Add the BlockList as a property on the Home document type
Create content with it.
Deploy schema changes to Cloud environment
Content transfer content to Cloud environment
Go to the Cloud environment to see the error when viewing the Home node