Utica Cutlery bayonet

This bayonet has an"H" mark just above the groove that engages the stud on the rifle, does it have any significance ? Also there is a slight groove at right angles to the blade just above the "UC", is this a characteristic of UC items or a manufacturing defect ?

Was the blade shortened? They marked them with a mark from the company that did the work. The grind could be some field repair of minor damage.

The letter H means it was hardened. You will find that on UC M1 bayonets.