I imported a walking animation from Mixamo to make custom enemy.but then snaps back to its original position, and keeps repeating this cycle.

[Hicsy]

Firstly, when exporting from Mixamo, if you choose “InPlace” down the bottom (and make sure it’s a looping animation) then it might be easier to use.

That said, I assume this particular animation is snapping back to it’s real position as per the earlier reply. Here is the documentation which explains exactly what causes that phenomenon:

Root Motion in Unreal Engine | Unreal Engine 5.6 Documentation | Epic...

^^
The jumping-forwards animation, in particular.

IIRC, In Root Motion: you can choose “Force Root Lock”… but there is also plenty of guidance in this linked article also.