HOOK Element

Hello,

I have been experiencing a lot of problems with creating and editing HOOK elements the last few weeks. It works on new accounts but an account that is worked on a lot will not see the HOOK editor after a while. When I want to create or edit a HOOK I only see the title and nothing else (see img). I have tried several things, other fellow students are also experiencing this on different wp sites. Is this a known bug and how can I solve this so that I can edit my HOOK elements again?