Too many endermen (holding blocks)!!

Endermen already spawn very much on warped forests, but i've heard that endermen holding blocks don't count to the mob limit, and this creates a bigger problem than it looks. For example, my portal is next to a warped forest, endermen spawn and pick up a block. The enderman who picked up a block doesn't count to the mob limit anymore, and wanders around to put the block down. While he wanders around, more endermen spawn and pick up more blocks. They pick up mushrooms (that multiply when on the floor, so they pick up more mushrooms) and don't despawn, and more endermen, and more blocks... and some endermen get stuck on places they don't want to or can't teleport away from, so they stay there with the blocks! The nether becomes a huge mess quickly and a sea of mushrooms, and the endermen get stuck and don't despawn, multiplying endermen and lagging the game/server. It's easily solvable, just make it so endermen holding blocks count to the limit or make a limit for them so new endermen don't spawn when there's billions of them holding blocks everywhere.