Thanks for updating on your fix!
It sounds like it might have been a bad-cookies issue in OBS; there's a way to manually purge those. For future reference, I believe it goes:
With OBS not running,
1. Go to C:\Users\YOURNAMEHERE\AppData\Roaming\obs-studio\plugin_config\obs-browser
2. Delete the Cookies and Cookies-journal files
3. Go to the Cache subdirectory, and delete the files inside.
This applies both to Browser Sources and the Docks system as far as I'm aware.