This article has more detail, because Apple spoke with iPhone in Canada: "Apple also gave some further technical information on the situation to iPhone in Canada."
"Apple explained to iPhone in Canada it has already fixed this performance issue through a server-side update, that will now allow macOS to cache Developer ID OCSP checks for a longer period."
Being discussed here: https://news.ycombinator.com/item?id=25107679
This article has more detail, because Apple spoke with iPhone in Canada: "Apple also gave some further technical information on the situation to iPhone in Canada."
"Apple explained to iPhone in Canada it has already fixed this performance issue through a server-side update, that will now allow macOS to cache Developer ID OCSP checks for a longer period."
I discovered this and blogged about it on Friday: https://lapcatsoftware.com/articles/ocsp.html
They comment on the OCSP issue but fail to comment on the Apple application exemption from filtering in Big Sur?
https://twitter.com/patrickwardle/status/1327726496203476992