Global Layouts and Form Layouts not saving

Hi,
We have been using Shotgrid for a few months now and everything has been working fine with creating and customising our Form layouts. Until yesterday…

Now, all the Version Form layouts have been reset to the original default (showing two fields only). When I go to Default Layouts>Version>Version Form and edit the global form there, the Save button does not commit any changes - it remains as Modifed (pictured), despite having Admin privileges
On the individual pages or the Version tab, when I choose Add Version to bring up the Form I can change and commit changes and they appear to ‘Save’. However, refreshing the page reverts it again!

I’m pulling my hair out here. I’ve tried resetting pages, relogging in, refreshing admin privileges.

There is no error message or anything appears so I’m stumped.

Am I missing something?
Please help!

I cannot change this Global Form:
!