Thank you for sharing your experience and I'm sorry to hear about the issue!
Were the schemes created in an earlier Archicad version?
If yes I would suggest trying the following method and see if it solves the issue.
The workflow to convert XML schemas between versions is to: - open a plan in the version where the scheme was created - import the scheme - save the file - open the file in the required Archicad version - export the schemes.
I hope this helps you deal with the problem. If it is not relevant I advise reaching out to your local support with a detail description about the issue.