Hi, it's definitely not a bug in OneTab that causes itself to be wiped.

OneTab storage is handled by Firefox, and is stored in Firefox's internal database format. For some reason, Firefox has wiped this storage area. Do you remember recently being asked if you want to "Refresh Firefox"? This is a prompt shown to you when you upgrade to a new Firefox version (there is a new Firefox version released every month). This feature, confusingly, wipes clean all add-on storage including OneTab's storage. You might have a folder called "Old Firefox Data" in your desktop folder, which could contain a copy if you used this Refresh feature without realizing.

The other possibility is if you had a browser or PC crash, which caused a disk corruption in the Firefox internal storage areas. Firefox would then wipe clean the affected storage area.

"Privacy cleaner" and "Delete unnecessary files" types of software can also delete OneTab data.