I also just found out that May 22 is when Gitlab is scheduled to release Mattermost 4.9. It would be nice to confirm if the same bug you mentioned before is actually the issue I am seeing. Because if it is already fixed, then I just need to wait a few weeks patiently. 
However, I would be sad if we waited and the bug wasn’t the one I’m seeing. :-/
If you have any suggestions or need me to try something, I am happy to do so.
Thank you!