Check the hub to make sure that the race isn't loose in the hub.
This usually happens on the inner race and it spins in the hub. The fix if this has happened is replacing the hub.
Also, when you adjust the inner nut, spin the hub a few times to make sure that the hub is all they way seated, sometimes the seal or the bearing will hang up
on the spindle and not be all the way in at first.
I an the others above are assuming that you did correctly repack the bearings with the proper grease before you assembled it.