1password support has confirmed this is an issue and they are investigating on it.
The support provide me a useful workaround:
In the meantime, one workaround is to use the Hide on this page feature to hide 1Password on the page/ session you are on.
Right click on the field> 1Password> Hide on this page
Note - this will apply only to the specific page you are on, and will need to be re-toggled when the browser is restarted.
As another workaround, you can prevent the autofill menu from opening automatically when the field is in focus by disabling the following setting in the browser extension:
Right-click the 1Password icon in your browser's toolbar and select Settings.
Go to Autofill and turn off the "Show autofill menu on field focus" option there.
Note - this setting will affect all websites. However, you can open the autofill menu when needed by clicking the 1Password icon within the field, or pressing the 'down arrow' on your keyboard.