MultipleResultsFound exception when editing group

When editing a group, I am presented with a 500 error page, and the attached error messages sent on mail and in the log file.

Steps to reproduce:

Log in with administrator

Go to Admin -> user groups

Click on a group

Expected result: Group edit window opens

Actual result: 500 error page

Reproducability: Always, when the error first has occurred.

This first happened when editing a group, and adding users to the group, removing users from the group, and then hitting save on the permissions side.

I was able to delete the group, and adding a new group where this issue was not present. Something might have gone wrong when updating the group the first time. Downgrading the issue to minor, since it exists a workaround for us.

Hmm i think i screwed up unique constrain on that table, need to check and try to reproduce that

in 1.3.X i'd rewrote those constraints that will add extra layer to make sure they're unique