It's very inconsistent for me even on just Firefox. On multiple systems running different instances of Firefox, checking with https://emudhra.we-have-a-problem.com/:
One blocks everything; one blocks 6 out of 12; one blocks the other 6 out of 12; one blocks nothing.
One blocks everything; one blocks 6 out of 12; one blocks the other 6 out of 12; one blocks nothing.