Tt600 Cutting Out When Changing Up Gear Up

Hi, has anyone had any issues with changing up gears on their TT600?
The gear selector works perfectly and selects the gear with little effort. It's only when the clutch is released, the bike cuts out, but restarts again instantly with a flick of the ignition and continues perfectly until I change up a gear again. The issue only seems to happen once the engine has warmed up and from gears 3 & upwards.
If anyone has any experience with this or any suggestions, it would be much appreciated!