Do you chill the beer and then filter? The reason I ask is because if it's chill haze, it's not apparent at room temperature so the filter won't filter it out.
Chill the beer in the original keg, and then filter/transfer to another keg and it should work out. Use the coarse pads first, then use the finer pads on the next run.
I don't filter my beer, but I've been considering filtering my wines.