In testing this with sites that don't work, I found that toggling Compatibility Mode on and then off again would temporarily correct the autofill and prompt on the page reload.
It's temporary though. After a browser restart, the same sites stop working.
An example for testing: https://gravityzone.bitdefender.com
Orion Version 0.99.125-beta (WebKit 616.1.22)
1Password for Mac 8.10.12 (81012007)