Warning: possible data loss with Excel

Cryptomator 1.6.14 / FUSE / OneDrive + win 10

It is now the 2nd time that data was lost when saving an Excel file.
After changes in an Excel file is saved normally.
Then the file is closed. There are no warning messages or notices.
After opening the file, it shows that absolutely NOTHING of the changes was saved!
As already indicated, this is not specifically repeatable.
Most times it is working.

I too have experienced this when modifying an Excel spreadsheet on Android using Collabora Office. Works most of the time, but on occasion modifications are not saved. Unfortunately I have not discovered a trigger for the problem.