This is my third flight with 22.214.171.124 and on the third flight I noticed the FMC SPD/ALT was all over the place along with the magenta line trying to keep up. It seemed to stabilize once in the air. This happened while I was sitting at the gate. I tried loading the plan again with the same results. I decided to fly anyway and once I got airborne and went direct to MPASS the problem went away. I noticed the magenta line was doing a loop after departure instead of a straight line to the next fix. To help I had 100 passengers and 13K on the gas for this flight. This will help with the ZFW and GW.