Am i doing something wrong about getting locking medallions?

Assuming a spymaster has 1/5 chance to get you a medal.

0.8^13 = 5.4% chance to get 0 medals,

17,87% chance to get exactly one medal. so it's not impossible you were just unlucky.

I have twelve spymasters and some runs I leave five locks on the ground, while on other runs only one will drop. You don’t really need any other medallions once your temple is complete so holding six locks whenever possible will provide a buffer against variance in drops.

No Just Bad rng, Happens from time to time.

There were runs where I'd rely on my smithies for locks, despite having 11 spymasters. Legion Garrisons were also quite helpful. What's not helpful in any way? 17 Armories! They're eating up a lot of your opportunities.

I have a feeling that bad lock rng is related to an instance or potential time of day. I once ran 33 spy masters without a single lock from them. They seemingly only dropped room medallions. Reset the instance and then dropped 5 locks. If I run my temple and get 0 locks from spy's on the first run then I just reset. Seems to work.

It may just be a coincidence, but this is a gut feeling after so many runs.