Try this: close the extra tabs, then Help/Troubleshooting, click Open Folder, close TB, delete session.json, the file that stores the set of open tabs when TB is closed, and the folder that was open at exit. Restart and close TB few times and see if it opens with just the tabs that were open at closing.

Thanks. Deleted the last .json entry and the problem disappeared. Three restarts all had what they should or should not have from the prior closing of TB.