I donw know what happening, but link ButtonMenu + child PopupMenu - doesnt work correctly if you create them from GUI.
I solve my problem by fully using code for it. Parent MenuButton was created by GUI and child PopupMenu - by code.
$ The problem in log: "node not found", he just can't see a child node if i set them by any ways except New.
1. var node = get_node("sublist") #error not see
2. onready var node = $sublist #error not see
But if you create it by GDScript - no errors all is fine.
SO if any people meet with that problem, the solve looks like:
If you want to do something like that.
Thanks anyway for hearing my call!