Sunbeam Cafe Series Conical Burr Grinder II EM0500

EM0500 Cafe Series Conical Burr Grinder II – has any one had issues with the grind settings? my grinder has a mind of its own. the settings change every few months, one time it was very course through out all settings then it was too fine to even extract through the group head. Then for some reason it goes back to normal.. im thinking maybe the burr grinder is loose but i dont wanna mess too much and void my warranty.