Quoted from PinMonk:OH. Your gate is working fine, it's just ejecting the ball to the right. It looks like the top of the scoop has bent up a bit from repeated ball ejects. Try bending the top down a little bit on the lower side nearest the playfield, not the edge nearest the backboard. You should be able to get the ball guided back to the correct trajectory when it ejects. You might have to remove that plastic on top before you can bend, though.
Alternately, you can loosen the assembly under the playfield and see if you can rotate it a little towards the backboard, then tighten it down. It kind of looks like it's going the wrong way on the eject before it even hits the scoop guide.
Great advice as mine does something similar occasionally ( no cliffy ) so will try these adjustments.