when are you planning to pull the drum? to see what's up.
when you do, post up pics and especially one of the drum. is there a "wear lip" on the edge of the drum? and did you adjust the starwheel after installing the drum or while installing the drum? i know a lot of people slide the drum on and off while adjusting, and if the drum has a lip, it won't be right. works good if you install new drums, though.
No lip on the drums at all. I did it while putting the drums on.