Only certain pages have toLowerCase

[kkhys2]

I am using version 1.2.0 of Hydrogen.
I am using the template code and have not changed the problem at all.

This time, when clicking from the product list page to the product detail page, for some reason TypeError: Cannot read properties of undefined (reading 'toLowerCase') is generated.

https://github.com/Shopify/hydrogen-v1/blob/v1.x-2022-07/templates/demo-store/src/components/product/ProductForm.client.tsx#L44

After reloading the page, the normal page is displayed.
Also, the error does not occur when transitioning by typing the URL directly.

I'm wondering if anyone knows anything about this issue, as the error is probably occurring at the point where a variation is generating the URL.

Thank you in advance for your response.