Cannot interact with stone altar in Jiquani's Machinarium

I have entered the jiquanis machinarium and collected to small soul core to progress. It is in my inventory but i when i interact with the stone altar it does not place the core in the alatar so i cannot progress. I have restarted, changed characters, changed areas, etc etc. Every time i return to the area the core is on the ground for me to pick up but the issue persists.