There was a thread about the “issue” approximately 6 month ago and I commented: Gibbering Gemstone - S28 250+ Chiltara kills no drop - #108 by KEA-2181
Well, because of the PTR now, each of the 7 or 8 times I was in act III went there to check. Chiltara was there 2 times (quite lucky!); “of course” no luck. 
Then when I got to the Altar part where the SoH is needed I started farming the other necessary pieces. Izual had a bad day but the 9th run he gave me the plan. Created a new char and started story mode. Other than my experience from 6 month ago, it took way longer until Chiltara was finally in the mood to drop the Gibbering Gemstone. More precisely a bit more than 70 minutes. With the 30 minutes of racing through Act I and II and the bit of III that is needed it took 100 minutes with a normal speedy GoD built.
Because Chiltara is guaranteed to be there in story mode if you get the correct cave (50% chance), and with a speed built that can find the cave in ~30 seconds (not “many” possible spawning points), racing to level 2 of the cave and find Chiltara in maximum 60 seconds, one can do “a lot” of runs rather quickly, and even knowing that RNG is still a b… Patience is a virtue and one needs to have some tenacity, because growing disconsolate is not an option. Anticipation is half the pleasure and when the Gemstone finally drops ambition turns to satisfaction. (enough proverbs for now I guess 
)
Compared to the hours one plays in a season that is still very reasonable in my very own opinion. And if one does not need the QoL options of the Altar (for me that is Double Death Breath, Double Bounty Caches, Pets Pick Up Death Breath, Pets Pick Up And Salvage, Double Legendary Chance from Kadala), one can completely ignore the SoH. But because I am a “completionist”, I’ll do that nevertheless…
All the best luck farming (next season(s))!