Jiquani's Machinarium bug

Jiquani's machinarium, first thing you need to do is pick up small soul core and put it into stone altar to progress, but it doesn't work. I tried to go back to city and all and it refuses to take it. This is my 5th character (10th time) and it is the first time this is happening. Doing the whole instance again will most likely fix it but thats not optimal.

Act 2 cruel difficulty

Edit: Doing the instance again fixed it. Just in case it's a problem with specific instance only, the one that was bugged spawned soul core far south from waypoint