it depends when did you buy it and from where, but I remember back in the old days whenever I bought a joss cue it usually comes with a Joss tip, I don't know where in the market you can find such a tip, but its been used before, and Joss tip usually is a tip that doesn't have layers and it looks almost identical to a lepro.
also there's good chance that you had a a lepro on it, but maybe a good one, and the one you are using now is a bad lepro, so if at all possible maybe try installing another lepro and see how it goes.