I am not sure that I completely understand your question. If I understand it correctly, when you tack the boat swings through the wind and continues to swing past the point that you want to stop swinging even though you are centering the helm.
There are a few posibilies here. First of all boats develop momentum in a turn that tries to continue the turn. You actually must turn the helm slightly past center and in order to stop this momentum and reverse the helm slightly in advance of when you want to stop the swing.
Then the jib may be hanging up on the shrouds. This backwinds the jib and pulls the bow off to leeward.
Another posibility is that you are losing to much speed in the tack. When a boat, especially a centerboard boat is going slowly the keel can stall out allowing the bow to pay off a little.
While the problem can be a fault of the design, rig tune or sail trim, more likely than not it is a matter of getting the feel of when to reverse the helm and how much to reverse it.