OK so i am trying to merge some polymeshes so i can export them as a single model and every time i try to merge them together i get some meshs merged and some not. Ive had this problem before trying to merge mshs and materials but thats def not the case here.
A buncha mshs i wanna merge:

All that actually gets merged:

stuff left behind:
Any thoughts on why some mshs merge fine and some just dont?