It wasn't even known until this happened. I didn't accept any missions related to it.

relanat 16 May 2021:

I have seen this once.
Possibly a wild goose chase but is it related to getting a BM ID at the hotel?
EDIT:
There is <Rumor> code in &stBlackMarketStation; which is well beyond my understanding. It seems to kick in after visiting the restaurant. This might be intentional to introduce players to the BM missions?

nms 16 May 2021:

Could be. I feel like if this sort of target is going to be set, it should be part of an explicit "visit this station" mission.