VKB-SIM

I got this joystick for a week now and I'm having this issue. The stick seems like its sticking when pulling it back. But after the first pull, it becomes smooth. It will have the same feeling if I leave the stick in the center position for a few mins and then pulling it back. Could it be the grease. I have taken the stick and base apart to inspect but I cant see anything wrong with it. I have even changed springs and the stickiness feeling is still present with no springs attached. Am i reading too much into this?

It takes a while for the grease to settle, it's high viscosity. You might even hear it popping inside from time to time.