I'm having similar issues to this. My structure is like so:
room_init - loads first takes care of prerequisite loading initialization
room_world - loads skeleton room with all the engine code (lighting, client, etc)
obj_world is also loaded in room_world and takes over the rooms loading process based off the players positioning information. When I load the room_pack data I process it to split my world up into a chunk grid, I rewrite the layers name to "layer_name + chunk_id" and cuts out any instances that aren't within the chunks boundaries (tiles are excluded the tiles are loaded separately). This is technically only 1 room cut up into multiple room data chunks that room_pack should be able to understand. This works sort of. The first chunk loads with all its instances (I excluded the tile layers since they aren't relevant I think):
Layer [layer_engine(7)] - Layer ID: 10 - Depth: -10099 - Tilemap<undefined> - Tilemap ID: -1
Layer [layer_light(1)] - Layer ID: 11 - Depth: -9999 - Tilemap<undefined> - Tilemap ID: -1
Layer [layer_shadow(1)] - Layer ID: 12 - Depth: -9899 - Tilemap<undefined> - Tilemap ID: -1
Layer [layer_client(1)] - Layer ID: 13 - Depth: -9799 - Tilemap<undefined> - Tilemap ID: -1
Layer [layer_player(0)] - Layer ID: 14 - Depth: -9699 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_interaction_1(23)] - Layer ID: 40 - Depth: 1100 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_npc_1(0)] - Layer ID: 39 - Depth: 1200 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_exterior_1(118)] - Layer ID: 38 - Depth: 1300 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_floor_1(15)] - Layer ID: 37 - Depth: 1400 - Tilemap<undefined> - Tilemap ID: -1
instance_exterior_1 / instance_floor_1 are chunk ones instances.
Then when the chunk next to it loads this happens:
Layer [layer_engine(7)] - Layer ID: 10 - Depth: -10099 - Tilemap<undefined> - Tilemap ID: -1
Layer [layer_light(1)] - Layer ID: 11 - Depth: -9999 - Tilemap<undefined> - Tilemap ID: -1
Layer [layer_shadow(1)] - Layer ID: 12 - Depth: -9899 - Tilemap<undefined> - Tilemap ID: -1
Layer [layer_client(1)] - Layer ID: 13 - Depth: -9799 - Tilemap<undefined> - Tilemap ID: -1
Layer [layer_player(0)] - Layer ID: 14 - Depth: -9699 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_interaction_1(23)] - Layer ID: 40 - Depth: 1100 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_npc_1(0)] - Layer ID: 39 - Depth: 1200 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_exterior_1(7)] - Layer ID: 38 - Depth: 1300 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_floor_1(0)] - Layer ID: 37 - Depth: 1400 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_interaction_5(0)] - Layer ID: 98 - Depth: 1500 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_npc_5(0)] - Layer ID: 97 - Depth: 1600 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_exterior_5(0)] - Layer ID: 96 - Depth: 1700 - Tilemap<undefined> - Tilemap ID: -1
Layer [instance_floor_5(21)] - Layer ID: 95 - Depth: 1800 - Tilemap<undefined> - Tilemap ID: -1
So you can see that chunk 5 loads 21 instances to the floor but now its showing that the instance_floor_1 now as 0 elements and the instance_exterior_1 has 7, which is very strange. This is how I'm loading the room_pack map chunks:
Any help is greatly appreciated!
Thanks!