`CdkDragDrop.previousIndex` is never being updated

[jeanbza]

It looks like CdkDragDrop.previousIndex is never being updated. It always reports the original index - rather than the previous - of the thing being dragged.

Reproduction

#18456 reproduces this issue.

Expected Behavior

CdkDragDrop.previousIndex has the "before this drag" index value of the thing I'm dragging, rather than the "before any drags occurred" index value of the thing I'm dragging.

Actual Behavior

CdkDragDrop.previousIndex has the "before any drags occurred" index value of the thing I'm dragging.

Environment

• Angular: HEAD (dev)
• CDK/Material: HEAD (dev)
• Browser(s): chrome
• Operating System (e.g. Windows, macOS, Ubuntu): mac, linux

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}