The title says it all. It literally takes about a full minute to import a web page to Scrivener.
I also experienced this in RC 11, and the same slowness is exhibited in RC12.
My environment: W10 2004, all security patches,
Browser is Edge Chromium Version 87.0.664.47 (Official build) (64-bit)
Any reports or discussion about the beta version should be directed to the Windows Beta forum. The other forums are for supporting released versions of the software. You can send a private message to a moderator to ask them to move your post to the Windows Beta forum so that other beta testers (and the developers) will see it.
I’m still not sure how to contact the admin.