That's pretty interesting, I find myself doing that with 3-5 youtube videos at a time. I'll watch maybe two and eventually close the window and lose the others.
Just reporting back that the transparencyreport page just says "some pages on this site are unsafe" without elaboration. It then offers that if I want details I have to give it individual page links at a time to see if they're the cause of the alert... Ugh.
That sounds like a healthy approach to web browsing. I dig it.