Many guns will do that, the bolt dragging over the next round in the magazine has enough friction to carry it forward.
Provided it's not an issue, don't worry about it. The round will probably get dragged back when the bolt cycles.
Often when loading double stack, double feed magazines, they will inevitably get bumped forward. A tap of the magazine spine on the wrist/helmet/table/tailgate will seat the rounds back and allow easy loading and feeding.
I've yet to have an issue with it, but I always smack my magazines at least after loading. Unless loading administratively, I don't look at the mag or smack it. Exceptions being when I've fumbled a mag into the dirt. Ones kept in a pouch outside extreme conditions should not be problematic.
When in the field, provided you can spare the noise and time, it would be cheap insurance.