I think this is a new thing - but today I've managed to Google my master password twice!
What's happening is that if I have the focus on the Chrome address bar - then click the 1Password icon the Login prompt appears with a flashing cursor - however the focus has actually remained with the Chrome address bar. So the result is I inadvertently Google my master password, which, obviously, is bad.
I've noticed the same thing happens even when it's unlocked - ie. instead of searching my logins, whatever I type ends up in the Chrome address bar also.
1Password Version: 6.6.433
Extension Version: 18.104.22.168
OS Version: Windows 10 Pro 1703
Sync Type: 1Password