Changes made on the order of Defects Issue Types are not always kept

Description

Changes made on the order of Defects Issue Types are not always kept. This happens as well for Requirements.

Pre-conditions

More than one issue type to be mapped as Defect.

How to reproduce

1. Go to Issue Type Mapping, and map the following issues as defects:
2. Add Defect in 1st place
3. Add Bug in 2nd pace
4. Click on Save
5. Then change the order of the Bug issue types
6. Save

Actual result/Attachments

The change is not saved. This is relevant when creating a defect from the Test Runn. the "default" bug issue type is the first issue type from the "Bug Issue Mapping".

Please see gif attached.

Expected result

The new order should be assumed.

Version
recreated in 4.1.6 and 4.2.10

Workaround
1. Remove the Bug from the Mapping
2. Click on save (keep only Defect)
3. Add the Bug to the desired place.
4. Save