Why would the Changeling Queen not kill?

To my understanding (once the Drone is dead), the Cangeling Queen would kill every night, just like a drone. And couldn't be jailed or partied either.

However, I just got a night with no changeling kill, after the Drone has been long dead. How could this happen?

My deaths before the night were Drone, Forger, Mule, Town Drunk, Spellcaster and Watchpony.
My orders were to Bodyguard a random pony, Gumshoe to investigate the Consort (found that out later) and Veteran to stand guard.

The Consort got killed by Pinkamena and the Bodyguard got role blocked. Veteran had no intruders.

What role could have prevented the Queen from acting? What could prevent the Queen from acting in general?