Reviewer is removed when adding new reviewer when at MAX_NUMBER_OF_ASSIGNEES_OR_REVIEWERS limit

Summary

Steps to reproduce

-Change MAX_NUMBER_OF_ASSIGNEES_OR_REVIEWERS = 4 in /gitlab/app/models/merge_request.rb

[5] pry(main)> Feature.enable(:limit_reviewer_and_assignee_size)

-restart gdk

-Open MR with 4 reviewers

-In the right-hand side side bar select an additional reviewer. OR -In the edit dialog page for a MR select an additional reviewer.

Example Project

What is the current bug behavior?

-New reviewer is added, a (arbitrary?) user is removed from the review. Screen_Recording_2022-08-30_at_10.47.11

What is the expected correct behavior?

Error stating that the MR has reached the maximum number of reviewers, similar to the error that occurs with quick actions

Results of GitLab environment info

Using version 1ca77cd9