yes did force to default settings that didn't help - throw it to trash and installed v92 that also not stop BS tabs, my guess are the problem persist on server side in my profile

using iMac v10.15.7 Catalina

You can check that those pages aren't set as multiple homepages.

You can check the homepage setting.

• Settings -> Home
• https://support.mozilla.org/en-US/kb/how-to-set-the-home-page

Firefox supports multiple homepages separated by '|' (pipe) symbols.

You can check for problems with the sessionstore.jsonlz4 file in the Firefox profile folder that stores session data.

• rename/remove sessionstore.jsonlz4 and sessionstore.js

You may also have to rename the sessionstore-backups folder.

When sessionstore.jsonlz4 is deleted you lose pinned-tabs and open tabs and you will have to recreate them, so if necessary make a note or bookmark them. sessionstore.jsonlz4 is only present in the Firefox profile folder when Firefox is closed.

You can use the button on the "Help -> More Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> More Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data