Can't cancel if the Group/Owner is invalid

If i do properties on a file, change the Group to an invalid group it will bring up a requester. If i now press Cancel the same requester is showing. I need to change to the previous Group before i can use cancel. It is the same for Owner.
This is the message:
"Current session allows changing ownership by UID only. It was not possible to resolve UID from account name "testing". Specify UID explicitly instead."

WinSCP 5.11.2

You can click the X button or press Esc key.

This issue has been added to the tracker:
https://winscp.net/tracker/1763