No, I believe that you're mistaken.
I tested with attackers with 5 damage and 20 protection (black hawks with army of gold). Against targets with 5 protection, BV was killing hawks left and right. But against targets with 30 protection it never even triggered. I even tested with "naked", protection 0, hawks against 30 protection enemies and BV never triggered. (Only the defenders had BV. There where no other effects or damage shields on the units. Fatigue was kept at 0 for the defenders.)
My conclusion is that my previous description was correct. The part about DRNs comes from reading the log. (Log diving isn't as fun as it sounds
)
I don't know how BV handles elemental damage or mistform. I wanted to test it but didn't have the time
I guess BV will handle BE the same way as mistform, since both BE and mistform activates after the damage has been dealt.