I saw that my water box can't clean sometimes and the jet chokes???
The Baffles sometimes break off in the OE water box and start moving around disrupting the outflow. If you remove the box from the ski and start shaking it to get the water out, after a bit, you may start to hear it rattle... that’s what mine did anyways.... it can be repaired too...
Also you running a flow control valve and restricter to your pipes stinger to regulate how much water your box is getting ?
Some pics might help
It can be something else as well
Like in my buddies case, his ski would load up in slow wakes zones and he swore it was to much water in the pipe and box.... well I isolated it to exhaust smoke back flowing in thru the scupper and choking it in slow wake zones...
Good luck