Hello,
I'm sorry to hear about your issue.
Based on your description, it sounds like something is corrupted within the project.
What I would do:
1. Save a .PLN copy of the project from one of the members who can still access it.
2. Open this .PLN with Open & Repair.
3. Re-share project on BIMcloud.
If you experience any further strange behaviour with your project, I suggest to contact your local support with an Archicad Teamwork SUpport Package and details about what you experience.
I really hope the repair and re-share will be enough though.
Let us know about the result.
Kind regards,
Noémi
Noémi Balogh
Community Expert, Admin