When you pushed the caliper pistons back into the their bores, you may have bottomed them out. Remove the caliper and take out the pad above the pistons. Put in a thinner piece of wood in the pads place. Just hang the caliper over the rotor, and have someone depress the brake pedal. Watch to make sure the pistons move. Sometimes crud builds up on the piston and or the piston bore, and will not allow the piston to move once it goes past the piston seal. If the pistons won't move, replace the calipers. If all works ok, you may have unseated a check valve in the actuator module, when pushing the pistons back into their bores, forcing the fluid back to the master cyl. Disconnect the battery, have someone press down on the brake pedal and crack all the lines, one at a time. See if that helps.