Hi Johnro,
Thanks for the details. To ensure we understand correctly, is this also occurring when you use Google Chrome web browser?
Let's test if the issue persists in safe mode. This will help to isolate the issue further to some installed login item or cached data. This guide has the steps to start up in safe mode:
How to use safe mode on your Mac
If the issue doesn't occur in safe mode, you'll want to follow the steps in this guide to test your login items:
Remove login items to resolve startup problems on your Mac
Otherwise, if the issue continues to occur, the next step is to create a temporary new test user account to see if it's occurring system-wide. This guide can walk you through those steps to test in a new user:
Set up users, guests, and groups on Mac
If you find it's also occurring in a new user account, we can recommend reinstalling macOS at that point. First, be sure you've created a backup of your important data. This guide can help with that:
Back up your Mac with Time Machine
Once your data is safely backed up, you may follow these instructions to reinstall macOS:
How to reinstall macOS
We're here for you if you've got any questions!
Have a great day.