Did you check the weight of the Bear at 28"? Bear is notorious for putting the approximate weight to the nearest 5# on the bow. They used to put the actual weight under the strike plate. It would not be unusual if yours is actually 52# @ 28", in which case it really isn't stacking much at all. I have seen several that were a pound or two off. I had a Black Bear once that was marked 45# on the limb, but 47# under the strike plate. My bow scale agreed with the 47#.
On the other hand, if it is actually 50# @28", then, yup, it is starting to stack a bit at 30". Neither scenario would be surprising.