dual piston calipers two pistons per caliper, the top piston is pushing out on both sides but the bottom is not moving on both sides

Mind that I have replaced the entire caliper on both passenger and driver sides, and bled both starting with the passenger side. This issue I was having with the old calipers and am still having with the new ones. They're not sticking. But only half working. Could it be a hydraulic pump problem? Couldn't be a hose issue because fluid has no problem coming out the bled screw and the brake isn't sticking. So I'm at a point where I think it has to be the pump.