You mean derailleur or shift lever?
I suspect: worn mech, B tension, cable tension.
Shift lever.
Checked everything else and am suspecting a worn mech to be honest. It’s not cable tension, mech alignment, stops, or, I think B-tension screw.
Just a note on the B tension screw though, I had it as close to the chainset as it would without catching and have backed it off gradually and this has made no difference. There’s not much else is there?
Will photograph my mech tomorrow and will need some advice on replacing it as I don’t have a clue what model I need these days (it’s XT 9 speed, that’s all I know!).
Thanks all.