Punch reel problem

[mark poulson]

Last year I bought three identical left handed reels with brass gears strictly for flipping/pitching/punching.
I typically lock down my drag for this application.
One of the three reels will sometimes not allow the thumb bar to release the spool. The other two work fine every time.
It can be released if I turn the handle a little, and it only happens in one part of the handle revolution.
If I back off the drag the problem goes away.
Does anyone here have any idea what might cause this problem?