Hello @MrSunshine,
I'm happy to hear you found this thread and that it's helped to resolve that frustration with the full screen mode. This issue with an accidental press of F11, has popped a few times now and I've included the details you've provided here in the issue that we're currently tracking internally. The team is discussing and looking at ways to make improvements to the full screen functionality of 1Password 8 for Windows. At this time I am unable to provide further details about how this may be addressed in the future.
Thanks for your feedback and have a great day!
ref: dev/core/core#15434