Are you using Orient Rotation to Movement within a character class? If so, you want to add a slight bias to the movement direction so that the character moves slightly in the direction you want to turn.
This may not be ideal for a side-scroller though, as after playing for a while your character may fall off the map due to the slight movement towards the camera. Ideally, you want to make your own function to rotate the character, rather than relying on Unreal’s (abysmal) Orient Rotation to Movement.