Hello,
i did an improvement request for clip to DevonThink a while ago asking to change the behavior in regards to attach directly to your current security context. Back in time i tested with Chrome and FF that for web pages that need a logon the clipper is opening a new session hence it it may be clipping the logon screen of the web site instead of the desired content. The web-clipper of Evernote did not have this behavior but some other tools clipping behaved the same.
I have seen the latest update of the FF extension was in may 2019.
So was the improvement request considered yet or will it be in the near future?