Getting incorrect size for tilemap

I have a Unity Tilemap that is 15x15 tiles.


When I get tileMap.size.x and tileMap.size.y, i get 75 for x, and 30 for y. 30 'almost' makes sense as it's 2x larger than 15, and the grid size is .5, but 75 makes no sense to me. The localbounds are also correspondingly screwed up.



Also i tried making a new 2x2 map with the .5 grid size, and it correctly gave 2 size.x and size.y.

The scales for the map and the parent grid are all 1, so there is nothing going on there. The grid is not the child of anything else which could change its scale.

Tilemap settings are all default, so the same for the 15x15 and 2x2 map.

I wondered if there were maybe stray tiles increasing the size of the map, but there is not.



I'm pretty much completely lost on this, I'll remake the map tomorrow and see if that fixes the issue to start fresh, but for the life of me I can't see what could be causing this weird behavior in my current tileMap.