NPC clipping in the ground while moving, why ?

Hello, I'm trying to script a titan (like SnK) which follows the nearest player. The problem is that my titan keeps clipping in the baseplate to follow the player, see the gif : https://gyazo.com/5d01a4061e65394400265d6504d200e1

I'm simply using the :MoveTo() method :

NPC.Humanoid:MoveTo(playerPos)

Any idea (I imported the rig using the "Rig Builder" plugin) ?Thanks in advance.

HipHeight problem. I just used a script found on devforum to fix it, that's it.