I have a new small Penn which had the same "issue". The issue was magnified when using a fast action rod as opposed to my older all glass rods. The reel is to pair with a rod for small jigs from 1/16 - 3/8 oz.
Could not work the small jig and detect a hit.
I did notice an ever so small bump when retrieving. Did not think this was the issue because it was so small, but compared to other much more expensive reels, noticeable. I sent the reel to Penn and they swapped a bearing. They problem is gone. As always - great service.
Hope this helps.