Solved. Went to settings about:preferences#privacy, chose Clear Data, checked the box to Clear Cached Web Content. It's been working correctly ever since.

That was very good work. Well Done.

ver 102.0 I'm having the exact same issue. The checkbox for "Open previous windows and tabs" is unchecked (I've cycled through that multiple times to no avail). Every time I open Firefox, it always load the previous tabs. I have also run Troubleshoot Mode and it has the same behavior. I have completely reinstalled Firefox, and I have also done the Firefox Refresh. I tried the step above and cleared Cached Web Content. That also didn't work. Anyone else seeing this issue?

Eric, the issue has reappeared for me as well. I also tried disabling and removing extensions, and that didn't work either. I'm not willing to try everything possible, but acknowledge there could be interference with security software, etc.

I have settled for a workaround, which once it has become a habit is somewhat less annoying: I simply open a new blank tab and then I close all other open tabs before I close the browser (with only that blank tab open). So when I relaunch the browser, probably it is just reloading that blank tab I had left open before closing it, but at least that is a lot less annoying than to have some previous site reloading.