Why there extra alert pops up when filling forms in Firefox?

When I'm trying to fill out some form field I always get an brwser alert and I have to click "OK". This is so annoying. I used a lot of password managers and all of them fill fields without alert window.
Why is this happening? Is there something that I can do to remove that alert?

1Password Version: 8.9.4
Extension Version: 2.3.7
OS Version: macOS 12.5
Browser:_ Firefox 104.0.2 (64-bit)
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