Sounds like it has worn a little and the balance between the idle jet & high speed jet is off a bit and needs adjusting.
FWIW then tuning you are supposed to leave them idle for a FULL 5 MINUTES to ensure that the carb & engine has reached a stable operating temperature.
Personally I would not worry about it.
Your problem could also be a change in the fuel formulation at the bowser.
This is one of the reasonas why so many top shelf hand held makers supply fuel in sealed containers because the locally available fuel can vary wildly day to day.