Having fuel pour out of the spring side chamber via the 1/4" hose barb is normal because it is tied to the return side of the fuel system circuit via a T fitting. Nothing prevents system return fuel from running into the spring chamber. In fact the action of the accumulator bleeding off system pressure draws fuel into the spring chamber.
Your vacuum test is what verifies a good or bad accumulator. When you get your new accumulator, perform the same vacuum Proof test too it and share the results please.