I'm trying to figure out what is triggering it.
I ran into this issue yesterday and again today. I usually use the autofill on Samsung Keyboard (same as you do with Gboard), but yesterday the autofill suggestion didn't show up when I was on a login page. So I opened the app and went to the autofill settings. The autofill was completely disabled so I tried to reenable it, and a popup took me to the Android settings for "Autofill services". There was a list with Google, Samsung Pass, and 1Password, but 1Password was already checked.
I managed to resolve it yesterday by changing from 1Password to Samsung Pass, and then again from Samsung Pass to 1Password, otherwise, the autofill on the 1Password app wouldn't mark the autofill as enabled.
I was trying to use the autofill and had to redo the procedure above again. To summarize, every time this happens I have to switch the autofill to some other app and then back to 1Password, otherwise, the autofill switch in the app won't turn on, and the autofill won't work.
I'm on a Samsung S20+
1Password Version: 8.9.3
Extension Version: Not Provided
OS Version: Android 12