I have the same problem as you... playing version 17.1. Were you have to figure it out or did you just console it?
For those who want details and have an idea of what to do:
My current save is before telling Madison that the sculpture is ready. I have checked countless times that the skeleton key is where it's supposed to be in the garage. After making sure it's there I tell her it's ready, go through the scene, etc. then Derek takes the key in my inventory. Go through bringing Patrick downstairs, talk to Derek about locking Madison in the bathroom, then finally go to garage to grab the key, but no key. I get that it's possible they changed what you're supposed to do from 13.3 -> 17.1 and if they did I have no clue what it is. To me, it just seems like a script error where someone had him take all keys regardless of location in an update between 13.3 and 17.1.