Issue with modulebuilder saving fields in docker

A colleague of mine created a new sugar install this morning using the repo. All seemed to working fine at first. After a while he started the containers up again and for some reason he can't add fields anymore to the module he was building in the modulebuilder. 

The only thing done was stopping the container (docker compose down ) and starting it again a few hours later. Any idea what this could be? We installed sugar in /var/www/html/  instead of /var/www/html/sugar/