Gear lever sound

Hello
I recently changed the gearbox oil and the timing belt+water pump.
I did not pay attention at first, but I now notice that when the car is stationary, in addition to the vibration of the gear stick which is minimal and normal, there is a sound from the gear stick,a kind of bzzzz.
If I move the gear lever a little back when the car is stationary (let’s say 1 centimeter or less) that sound disappears and only the vibration remains.

While in gear, that sound also disappears.
I don’t know if the problem is related to the recent changes but it appeared after that.

PS:I made sure the oil changed was exactly according to my car specs.
Thanks

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