How does Fastmail work in Monterey with 1Password 8?

I connected my Fastmail and 1Password accounts, but when I try to add a new email to Facebook, I get both Apple's popup and the 1Password autofill overlaying each other. I have to turn off "autofill from contacts information" in Safari to even see the 1Password "list" (it looks like a plain rounded rectangle, not anything familiar to my Mac eyes) but there is no create masked email option.

I am on this page, trying to add a new email: https://www.facebook.com/settings?tab=account&section=email&view

I also cannot find a way to generate an email when editing my account in 1Password 8. Selecting my email field brings up another rounded rectangle that has my existing email address in it twice.

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1Password Version: 80202072, on BETA channel
Extension Version: 2.1.0
OS Version: 12.0 Beta (21A5522h)