yes it is... you are bleeding it wrong. You have to remember that the whole brake system is 1 single hydraulic system. So, air must be bled on all 4 corners. Having said that, you must also bleed them starting from the most remote caliper to the closest caliper (in relation to the master cylinder). So, bleed it in this order:

1) Rear passenger
2) Rear driver
3) Front passenger
4) Front driver

Make sure that your "method" of bleeding is proper. The way I do it is very simple and can be done without asistance.

With the brake fluid reservoir in full amount and the vehicle is raised up as horizontally even as possible:
1) after the bleed port is slightly loosened, connect a hose/tubing and submerged the other end of it in a container filled with brake fluid.... keep the hose end always submerged in the fluid. This will allow the air being bled to escape during the downstoke.... then suck fluid during the upstroke. Pump the pedal several times then tigthen the bleed port.... repeat it on all corners....constantly check the fluid level in the reservoir