Riot's known about this and called it a bug over a month ago on the PBE, but it's still not fixed.
The 20 minute duo barons are getting old.
It also does a minimum of 8 damage per stack, which means against targets with less than 640 hp, it does damage as if they had 640 hp. Not really game breaking, but some hidden power that should be included in the tooltip.
Myrddin1 votesYeah it most likely should have a cap, then again kalista should also have a rend cap vs monsters
MealReadytoEat2 votesThe only other % hp that's not capped vs monster is Amumu's W I believe. Pretty consistent design philosophy.
Myrddin1 votesI entirely agree, she burns dragon and baron too fast.
Flawless Fetus1 votesnasus ult has no cap
layrit1 votesBut she only burns them really fast if she has A LOT of stacks.
TeCoolMage1 votesCan we have a Kalista reminder too
Only Play Darius2 votesTo be fair that's what they have decided to balance 
around. She was designed to be an asset to the team regarding neutral objective control and that's what makes her unique as an ADC.
However, she has way too much power in her hops and if Riot insists on not nerfing her hop distance, then she will HAVE to lose everything else in her kit, including her objective control. So sad to see champion kits gimped by refusal to remove toxic gimmicks (
and his double crit)
Photos of Ghosts1 votesThey DIDN'T call it a bug. They said "that might be too much, we'll see if it needs caps - in particular on epic monsters."
MealReadytoEat1 votesIt's absolutly a bug. Meddler said I was meant to be capped at 75 vs monsters, but that bugged out.(http://boards.na.leagueoflegends.com/en/c/gameplay-balance/THNELApb-after-6-stacks-kindred-wolf-should-hunt-dragonbaron-only?comment=000000000002)
Photos of Ghosts1 votesherp
ReZisT Lust1 votesDeny her marks .hen they are shown on the map