AppInventor - disappearing blocks

[FishCustard]

We use AppInventor as part of our KS4 IT curriculum (we run it on a VM on each client machine), and are experiencing a very odd issue with certain students' work disappearing. They create their blocks in the blocks editor, save it, and then at some later point they find that the blocks editor is empty or missing large sections.

 

It's happened to about four students so far, and as everything is saved on Google's end there's nothing we can really do about it. Has anyone else experienced this/come up with any mitigation strategies? Could it be an issue with lots of access to the app from one or two public IPs on different accounts?

[FishCustard]

I hate to 'bump' threads, but I imagine this is the only place I'll get sensible answers to this - any ideas welcome!