I think this is a problem with Replace NPC and alpha dinos. I have 8 other dinos that are remapped to inherited versions that enable breeding, and all of them behave as expected (including properly respecting the limits on the original). Even in the game, using [FONT=Courier New]getallstate with the original dino’s blueprint ID will pull up all the instances of the remapped npc.
I’m not adding entries to the spawners; I’m just using Remap NPC. With every dino except the mosasaur, this works perfectly. It’s automatically placed in the same spawners as the original.
Unfortunately, I don’t believe the Alpha Mosasaurs are being spawned using anything public, since they don’t seem to be referenced by any spawners (and the weirdo behavior when you try to replace them with an exact copy of themselves).