octaves are weird on my new horn ??

i got a yts 875ex a while ago and its had an issue with octaves/leaps. this ONLY happens when the G key is being pressed (so the smaller octave key is opening) keep in mind im primarily a tenor player and have NEVER had this issue ever on any other horn. is this like an issue with the horn or is it unique to this specific horn ??? its driving me nuts since when i play fast passages with leaps it does not respond fast enough. its driving me INSANE. my previous horn was a 62