Confusion/Errors when deleting repository that is used by checkout task

Removing a repository on the plan level,
a) does not delete usages of it from the JOB.
b) it also doesn't warn you that your build will be screwed.
c) is actually allowed even if it is being used.

I immediately pressed play after removing the repo and the build failed with "can not find repository with id 568445".

I then go to edit the source directory task and I see two checkout items with the SAME repository picked in the drop down (becuase presumably the UI couldn't figure out which one to pick so picked the first.)

I am not allowed to remove the first repository checkout - even though that is the one that is technically broken

Build Working Directory is reverted to "Default Working Directory", even though this is never used as the dedault anywhere else (The first checkout repository was always selected as the default when I didn't pick anything)