I had that problem but it was the boots that would make my shifters pop out.
Rockaholic here with my new (old) user name
Mine is a different problem not caused by the boot. The problem is when the rear case is in 4WD, the right side shift rail is moving backwards, into the 2WD position. Then when I pull the shifter back into the 4HI position the shift rail keys are not lined up so the shifter won't mesh with the right side shift rail and it gets jammed into the 4HI position. Then I have to pull the shifter out and slide the right side rail forward with a large screwdriver to get it back into 2WD. Very annoying!
Anyways, I installed the new Heavy Duty springs and wheeled all day Saturday. The new springs did make a huge difference. as a matter of fact, I didn't ave to pull the shfter once. But it did still get jammed once so I don't think my problem is 100% fixed. I must have done something wrong when I assembled the rear T-case. I guess I'll call Marlin and see if he has any ideas.