Meaning the servos might be set to move too far. For example the steering on the buggy can only move only so far before hitting some physical travel limit. If the servo is trying to move farther than that limit, bottoming out the steering, it can draw a lot of power, especially if it’s a modern high power digital servo. Possibly causing the type of issues you seem to be experiencing due to resulting voltage sag of the receiver battery. Also it’s very hard on the servo.

At full left and right turn of the radio, there should be a little play/clearance left in the steering mechanism. Through out the suspension travel too. The same applies for throttle and any other channels.

Not familiar with your radio, but a quick check of the model on Futaba’s site indicates it has EPA for all channels (End Point Adjustment). This allows adjustment of how far the servos will move in each direction.