I was trying to register a new credit card at discover.com/activate. The web form allowed me to select the login+password+number on the back of the card. When I tried using the 1Password extension to fill the form, it appeared to fill successfully (on Chrome and Safari on my iPhone), but afterwards, the keyboard was completely non-responsive. both Chrome and Safari would crash. When I got back to the springboard or any other app, the keyboard would crash continually. I had to reboot multiple times to restore keyboard functionality.
This happened several times. I did a work-around by copy/paste from 1Password.
I've tried a couple other logins, but didn't reproduce this error. I think the issue might be an interaction where it was trying to trigger the numeric-only keyboard for that third item. I tried disabling all third-party keyboards, also to no avail.
I suspect this might be an iOS issue, but I thought I would mention it here just in case.
1Password Version: 7.0.6
Extension Version: Not Provided
OS Version: iOS 11.3.1
Sync Type: 1Password for families