Unable to decrease required approvals

Summary

When editing a MR, you can increase the number of required approvals, but not decrease it. This leads to situations where you cannot get enough approvals once you started with the wrong number. When clicking on Edit of the MR, it shows the correct amount of required approvals, however on the MR page itself it shows the maximum.

Steps to reproduce

Create a MR, set a number of approvers (e.g. in our case 4). Edit the MR and reduce the number of approvals required. The page will still show 4 circles and the MR cannot be merged.

Expected behavior

Correct amount of required approvals

Actual behavior

Maximum amount it once had.

Relevant logs and/or screenshots

On the left a MR, on the right the Edit page of that MR.

Output of checks

Gitlab 8.16 upgrade from 8.15.4 using omnibus. Both chrome and safari show the problem.