After deleting an account associated with a user, the user is irrecoverably corrupted

[johanbrandhorst]

Describe the bug
When deleting an account associated with a user, it becomes impossible to reassign an account to the user from within the UI.

To Reproduce
Steps to reproduce the behavior:

1. Create a user, an account and associate the user with the account.
2. Delete the account.
3. Navigate to the users page.
4. Click the "Accounts" tab. A white screen is displayed (the subsection of the UI seems to crash). Reloading the page instead shows a "Resource not found" page. At this point, it becomes impossible to reassign an account to the user through the admin UI.

Expected behavior
I expected to be able to reassign the user to another account.

Additional context
See recording for an overview of the bug:

user-account-deassociation.mov

[ZedLi]

We found the underlying problem and it appears to be unexpected data causing the irrecoverable corruption. We'll update this issue when we have a fix in place.