A recent update to your Firefox browser extension seems to have created a problem for me.
When the browser extension is locked, and I click the 1P button in the browser window, the content of the master password entry screen is too big for the popup:
If I blindly type my master password and press enter, the extension unlocks successfully and from then on appears to be scaled correctly.
I'm not sure what could be causing this issue I'm afraid. (Neither of my monitors is high-DPI)
1Password Version: 8.2.2 (beta channel)
Extension Version: 2.1.2 for Firefox
OS Version: Linux (Fedora 34 on Wayland)