EMB 135 aileron sag
 

I'm starting to wonder if I'm imagining things. The EMB 135 we fly shows an interesting characteristic I can't explain.
Down
After shutdown, the right aileron sags by two inches within minutes while the left is still neutral. There is no evidence of leak and engineering has found nothing. If the hydraulics are energized, it is neutral and rock solid.
It just seems that the hydraulic dampening is very weak on the right side.

Any insight?

I don't know anything about Embraer hydraulics or flight controls, but if it's similar to Boeing/Airbus you can do some additional troubleshooting by putting 1 hydraulic system on, then off and the next hydraulic system on. The flight control shouldn't move. If it moves one of the actuators is slightly misrigged and can force against the others. If on shutdown the bad actuator is the last to loose hydraulics, it can still force the control down.
Hydraulic damping should be done by all actuators on that flight control, so 1 bad one shouldn't be a problem.
Again, maybe EMB is different, but it's a start