Health component on shadow tentacle and lunar plant tentacle leads to buggy behavior

The Lunar Plant Tentacle that Wormwood spawns and the Shadow Tentacle spawned by the Thulecite Club have a health component to them where they both have 500 hp.

The problem is that mobs will try to attack these tentacles, never do any perceivable damage to them and then disappear as their allotted time slot is over.

This leads to extremely buggy behavior. When fighting Bee Queen, the Grumble Bees will chase the tentacles but won't actually damage them. When fighting spiders, they lose their focus on the player and instead try to go for a tentacle they can't even touch.

I suspect it is the fact that they have health to them that is causing this behavior, but I'm not entirely sure.