bug(CdkDragDrop): cdkDropListOrientation="mixed" reports wrong currentIndex

[xeladotbe]

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

Drop Event returns the wrong currentIndex if you drag the element straight up to another list and back to the original position

Reproduction

StackBlitz link: https://stackblitz.com/edit/4gs3gqno?file=src%2Fexample%2Fcdk-drag-drop-disabled-sorting-example.html,src%2Fexample%2Fcdk-drag-drop-disabled-sorting-example.ts
Steps to reproduce:

1. drag Bananas from the list straight up into the other list (Cucumbers moves to index 1)
2. drag the element straight down again to the old position in the list and release

Expected Behavior

drop event reports previousIndex = 1, currentIndex = 1 as there was no change of position

Actual Behavior

drop event reports previousIndex = 1, currentIndex = 2

Environment

• Angular: 20
• CDK/Material: 20
• Browser(s): Chrome
• Operating System (e.g. Windows, macOS, Ubuntu): Windows, macOS, Ubuntu