I tried following this tutorial:
So my character can look at enemies while its animation plays.
I first tried it using a model from mixamo, which worked perfectly. But, I tried using the multi aim constraints on my own character and now it freaks out and floats in the air. Not sure if anyone found a solution but it’d be much appreciated!
I have the same issue 
Have you found a solution?
Looks like root motion is breaking it. Try changing the animation settings.
what do you mean? is there a specific setup in the animation settings for this to work?
If your animation uses root motion or you don’t setup your model object correctly then it’s going to give you bizarre results.
Enabling IK Pass in layer settings (in the animator) and apply root motion in Animator Component fixed this issue for me!
I got this problem too, with a model/rig from blender animated with mixamo, it was due to Armature scale in unity set to 100. In blender during fbx export i set scale dropdown to “unit scale”. Armature scale is now 1 in unity and constraint animated model stopped floating or offseting