POE2 - quest item disappeared

I was following the trial of chaos quest and killed the chimera in act 3. After it dropped the quest item „chimera inscribed ultimatum“ I tried to pick it up. Unfortunately my inventory was full and the item disappeared in the second I clicked on it.
How can I get the item back?
-Tried to reopen the instance
- searched my inventory and stashed (no item)
-Killed the Chimera again (no quest item)
- Tried to group up with someone else to continue the quest but also no progress

Is there any way to restart the whole quest? Or is my character now blocked to continue with chaos trials?

Same thing just happened to me. Killed the chimera, tried to pick up quest item but inventory full. Quest item is nowhere to be found. Have you had any luck finding a work-around?