@ts678; I didn’t have to wait very long before the warning re-appeared!
From looking at the log file, it would appear that my issue is pretty much the same as what you have experienced with Google Drive and fits your explanation (what you explained helped me understand the log file - thank you!).
What is also interesting from the log file is that I am experiencing 403 forbidden errors on a regular basis, which retry successfully, but because the backup doesn’t require any delete operations it doesn’t flag any warnings.
Here is my log file: Desktop.zip (3.6 KB) - the log contains other days in it and the backup warnings were flagged for today’s backup: 2020-05-13.
I recall that Google Drive has limitations (like other free storage sharing providers such as OneDrive) and I wonder if this is the cause of the 403 forbidden errors. I quick google brings up this Stackoverflow question.
Thank you.