Hard Bricked -- Dropped Large Soul Core

So basically I dropped out large soul core, it immediately disappeared and I couldn't pick it up. Went back to Sanctum and can't get a new one either.

Please fix & help with this issue and it stops me from progressing entirely.

Friend of me has the same problem. Let‘s Hope for a fast fix

Here to say: have a friend or someone from discord who is *done and gone* with Act 3, they can come back and get medium soul cores and spawn the boss again to continue. Just unbricked my character with this. Had the same bug, lost my instance with the Large Soul core on the ground and had to find a way to respawn the boss.

yeah was the same for him he searched after a public group and after the other guy puts the core in the socket he got the quest completion