Great! Is that the third motor, or the second motor?
On a wing, you have two control surfaces to control 2 axis. When you roll (right stick left and right) those act as ailerons. Right stick pushed to the left, the left aileron should go up and the right one should go down. It appears yours are behaving correctly.
When ailerons are also used to pitch up and down, they become elevators and move together. We can call them “elevons” because they combine aileron and elevator. You have no “flaps” on this airplane.
It appears that your elevator (when the elevons move together in the same direction they are doing the job of an elevator) is backwards. When you pull back on the right stick, both elevons should go up, it looks like yours is going down. You can reverse that in your transmitter.
Is that the third motor, or the second motor? - This is the second motor, it turns out, all this time, I was using the 1st motor
On a wing, you have two control surfaces to control 2 axis. When you roll (right stick left and right) those act as ailerons. Right stick pushed to the left, the left aileron should go up and the right one should go down. It appears yours are behaving correctly. - Ok, that‘s good
It appears that your elevator (when the elevons move together in the same direction they are doing the job of an elevator) is backwards. When you pull back on the right stick, both elevons should go up, it looks like yours is going down. You can reverse that in your transmitter. - Ok, I will do that