Form Fields getting hidden

Hi,

I've encountered a strange behavior in our CRM Online Instance:

I have multiple Forms with "missing" Fields for e.G rollupquery. If I open the form editor they exist on the form and are published. 

But they're still getting hidden by something! When I use a script in the console to unhide all Fields on form, they appear.

There are no custom Scripts on that Form, it's completelly vanilla

I've tried:

- removing and adding them again

- using the new & old Solution Editor

- importing the Form from a vanilla CRM

- Modifying the Solution per text editor

but the result stays always the same.

Any Ideas?!