Try re binding the transmitter to the receivers, make sure you're using 2 different model memories between the sct & buggy.

When re binding make sure your end points are both set to 100 for left and right, make sure your trim is set to center and then use "sub trim" to get the steering centered before making any trim adjustment.

Be sure to re calibrate your esc's to your radio after the re binding process.

Cheers
Rob.