Stuck in Act 3 Jiquani's Machinarium

so first of all I cleared Chimeral wetlands 4 times looking for the entrance to Jiquani's Machinarium. I ended up having to get a mate to teleport there to i can tp to them then i went to find the small soul core and now it wont let me put it in the alter.

Yes, I have the same problem. It's also reported here (see last 3 posts): https://www.pathofexile.com/forum/view-thread/3597861

Kinda annoying because now I can't continue the game. Hopefully it will be fixed soon.

Seems to be fixed - after booting up the game again today, Alva wasn't spawned in the area yet and after finding the stone again I was able to put it into the stone altar.

I'll add my self here, same place stuck before stonr altar, and the small core is nowhere to be found, cleared whole level

Plus one to not being able to find the stone Cruel difficulty.

I also got stuck in Jiquani's Machinarium, but my issue is related to being interupted while attempting to place the small soul core into the Stone Altar; after clearning the mobs that interupted me, I am unable to place the small soul core (still in my inventory) into the Stone Altar to proceed through the Machinarium.

As of today, I am facing this issue. All the stones are activated and all doors are opened. The main boss is defeated too. I am still unable to enter to Jiquani's Sanctum. I won't be able to progress in the game because of this issue.

Same issue here.
I have the Small Soul Core in my inventory but clicking on the Soul Altar does nothing.
Restarting the game didn't help.

=== Workaround:

Let your character die. That unsummons Alva. Do NOT summon her and use the stone.