Shot in the dark, but that delay should definitely be unrelated to a cast change. HHN has two sets of backup actors: Reserves, who may choose to be there on any given night as part of a central group for any holes in streets or houses, and the Fire Crew, who are required to be present as an understudy for their own house or street, I believe. The way cast changes happen, at least for characters like in Trick R Treat that primarily come out of “boo holes,” is referred to as a “tagout,” because the replacement actor literally “tags” the person currently on by tapping their shoulder to say “once you come back in, you’re done for your shift.”
Long story short, I watched Seeds go down like that, with the house lights on, actors away, and the line delayed for a while. Because the break room for Seeds is in that parade building, you can’t see them go away in hoods, but my boyfriend was part of that cast and shared that fact. There had been a nosebleed within the house that prompted cleaning up for the sake of both the guests and the actors, and they spent a very thorough amount of time sending their crew through to assure that it was safe and clean. Things like that could be a possible reason for what happened to you !