Ya thats sort of normal tho if its drifting a lot a compass recalibration can tighten it up to drift less and also to stay pointed in the right direction.. On mine I also notice it drifts a lot more the closer to the ground that it is. I think that's from it not having as good of a lock on as many PGS satellites or interference from near by ferromagnetic objects.
But if up over about 10-20 feet in the air or higher it seems to drift a lot less and also dont bob up and down as much If I go a lil bit higher mine usually only drifts a few inches in gps mode. and just stays almost perfectly stationary.
Its when i get down low and just a few feet from the ground then shes all over the place. But with in the few feet limits.