Atlas Map Node Question

I'm trying to make nodes that are irradiated, coalesced and have a boss so that I can put a T16 in and get my 7-8 boss atlas points. I've been painstakingly pathing to these towers to add bosses to these 2 maps. I put in a 7 map boss tablet, and got a warning that only 5 nodes in range could have bosses added to them. I didn't count every map in range that had a boss, but there were a lot, so I just figured these 2 nodes were included in the 5 eligible nodes.

Can someone explain to me why bosses couldn't be added to these 2 nodes? This is getting a little frustrating at this point trying to get a node that I can put a T16 into to get these atlas points, I need to know if I'm doing something wrong.

Thanks,

I think because not all maps can generate boss arenas. Don't think it's entirely based on map type either, as i know there's a boss for Steppes sometimes. So might be something about the maps seed that prevents a boss arena being placed?

Just my guess.