How to use "Game Animation Sample" from Epic in a Animation VFX Project ?

Hello,
I want to use the animations from the Game Animation Sample super pack for an animated film.

So I used one of the character blueprints “SandboxCharacter_Mover” in my level and I move it along a spline with the sequencer.

And it works.. the character move.. BUT he is flying.

I tried several heights of spline but it still seems to be moved in height at the time of Beginplay.

the height is well detected but the height instructions of the spline force the displacement in height.
I can’t avoid it

Could you help ?
Is there an other solution ?

Maybe the NPC system ?