Testlive, singleplayer, no mods.
Possibly a bug, possibly intended change (possibly just odd RNG) -
I’ve had a few incidents now of two Black Kappa/Corrupted Shalebacks spawning at the same time in the same small area(replacing two normal shalebacks, so it’s not like a duplicate spawn issue or anything) - it just seems very unusual for whatever rng chance they have to spawn to trigger two at once. The first time I thought was just a random occurrence from rng, but for it to happen a few times seems particularly odd. (Has happened at different shaleback spawn points, so it’s not location specific.) It hasn’t happened with eg Corrupted Croc or Corrupted Hyena (they have still only spawned one at a time with the sort of frequency I would expect) - it just makes me wonder if something odd is going on with the spawning for Black Kappa/Corrupted Shaleback.
On a related, but different note - Imps are sometimes respawning unusually fast - several times now I’ve killed one only to see it immediately respawn in front of me. The cheeky little spuds don’t even use a bedroll 
(It was definitely more trick than treat the first time it happened, lol).