Variable speed on DSG-AG 125

[paul U]

I am looking at purchasing a minimally used Grinder DSG - AG 125. On inspection when you first start it up or wind the variable speed up the motor spins quite fast before slowing back to the set speed. It seems to otherwise run fine. Is this a normal function? Is it intended for a reason? All my other festool products with variable speed do not do this.
Thanks
Paul