A fake predator sometimes shows up when an actual Predator player exits a game prematurely. They A. if he exits alive- fake predator takes over and executes the self destruct....(i cant validate this but it is my assumption--because some games when I see the predator leave the game entirely , he will self-destruct but all the way on the edge of the map corner which leads me to believe his placement isn't in check)
B. If the predator is downed and ready to do self-destruct and predator player leaves, a dummy might take over his body and instead they give him a second wind and AI takes over.
Why there is predator sounds during your solo game when no Predators have spawned is beyond my knowledge.