no sorry mate not on mine it defrost the same here. This may
help though.
If you have the climatronic setup you could try resetting the vents and the aircon by putting it into diagnostics mode.
Press the ECON and the top middle button (central dash air vents)
the air con unit and vents do a full reset/diagnostics.
if you have the temp switch set to move the temp together on both sides you will need to set this again by just holding the AUTO button for a few seconds. then the temp selection works in tandom with each other and not separately.
btw... just some info on the windscreen button..
The air drawn in from outside the vehicle is directed at the windscreen. The air recirculation mode, if switched on, will be switched off as soon as the defrost function is switched on. At temperatures over 3°C, the air conditioning system will be switched on automatically and the blower speed will be increased by one level in order to dry the air.
FYI using your aircon correctly can dry out the windscreen quicker than just heat alone.