Error when deleting more than 2 groups in the Webinterface/GUI

Description

When deleting more than 2 groups on the GUI, FD throws an error, but deletes the groups.

The error message: "Failed to compute DN for object: Failed to create a unique DN"

Distribution Name and Version

Whatever is on demo, demo-fixes

FusionDirectory Version

1.2, 1.2 fixes.

PHP version used

Whatever is on demo, demo-fixes

Origin of php packages

Whatever is on demo, demo-fixes

Steps to Reproduce

1. Select 3 groups by ticking off the boxes to the left of them
2. Delete them all by going to Actions -> Remove
3. Observe error message

Expected behavior:

Any number of groups should be deletable with no error being thrown.

Actual behavior:

Error is thrown when deleting more than 2 groups at once.

Error message: "Failed to compute DN for object: Failed to create a unique DN"

I think the message is different across versions of FD.

Reproduces how often: 100%