Normal, run of the mill checkout, from this site: https://weaveskart.com/checkout/
Got my addresses in (prefilled by cookies in site from past orders), got to the credit card entry, copy/paste each bit from 1 Password (still non-functional as an extension), and then it couldn't process the card.
Opened the exact same page in Brave and zipped right through. And much easier, because 1PW extension DOES work, flawlessly, on Brave, like it does on Safari.


As noted, Compatibility Mode was ON.
Checkout with credit processor.
0.99.128.2.1-beta (WebKit 619.1.11.111.2)
Sonoma (14)