I believe there is a bug with spawnable actors in 4.12 sequencer,
I created an actor blueprint called MyActor and added it to the level.
Then I added a sequence to the level and set it to auto load.
Then I added MyActor to the sequencer and converted it to spawnable. Now if I open the MyActor blueprint and compile it, it won’t show up in the level anymore, and won’t show up when playing the game.