It's clearly bug, bow ult is 100% hp desync, but not only, still trying to figure out what other things cause it
Can't believe I got my account suspended for some bulls--t XP gains I never even noticed, but there are clowns running around exploiting Ballista every day for months who never get banned!
Can reproduce by putting dot on player and then casting bow ultimate. It doesn't have to be bow got but it is triggered by dot then high damage. It's like the dot isn't ticking while you are being channeled and then the entire dot is dumped on you. So you don't have 10k over 6 seconds or whatever its 0 for 5 seconds then 10k on the 5th while the channel is hitting you too.
Annoying for sure and that was undeserved baggage