Because you're re-using the tiles for other land in the game, when you use the copy (CTRL-C) or click-drag to make a new blueprint, it tries to copy the normal land tiles. (I discovered this problem on Fulgora, but from your description I think it's the same on all planets.) This is probably also why you can't undo (CTRL-Z) the placed tiles.

You should instead define new tiles that can be placed, just like normal landfill is a new tile. You should be able to re-use the same graphics, but the actual item and tile definition need to be new.

Thanks, I was not aware about the tile, thought it would just be a graphic reference, but it is a normal object in the table.
Also needed to add minable result to it, then it works.
But regardless, thanks, I would not look into making a new tile object.