But I was getting it (until 2 days ago) from Firefox, not from my AV. So it must be upstream of the browser.
I'm not a teacher yet, but I am studying a Bachelor of Education with an English Literature major at Charles Sturt University, in NSW, Australia.
There are no warnings being issued any longer.
If you are still seeing them then this is probably due to your browser's cache. Clear your cache out and that should fix any remaining problems you see.
I'm not a teacher, so please consider any advice I give in that context.