Magenta rectangles

Hi all
Apologies in advance if this isn't the place for this:
Noticed a mention here of "magenta rectangles" - https://www.noodlesoft.com/kb/hazel-catalina/. Since updating to Catalina my entire system has had a magenta/pink screen until I begin the login process. I don't know if it's actually Hazel causing the issue but I can't find any mention anywhere from Apple about a "magenta window" bug/feature (undocumented changes from Apple in 2019? Surely not XD)
Is there any more information on this available anywhere? I'd like to debug if there's some app running on my Mac that's opening a massive window at login that was invisible in Mojave
Cheers
Luke
Apologies in advance if this isn't the place for this:
Noticed a mention here of "magenta rectangles" - https://www.noodlesoft.com/kb/hazel-catalina/. Since updating to Catalina my entire system has had a magenta/pink screen until I begin the login process. I don't know if it's actually Hazel causing the issue but I can't find any mention anywhere from Apple about a "magenta window" bug/feature (undocumented changes from Apple in 2019? Surely not XD)
Is there any more information on this available anywhere? I'd like to debug if there's some app running on my Mac that's opening a massive window at login that was invisible in Mojave
Cheers
Luke