DDJ-1000 Crossfader off centre (again?)

I have had this issue some while ago.  it occured when upgrading from firmware 1.05  to 1.06  (i believe?)   but was fixed  when upgrading to 1.07

i don't use the crossfader that much  and therefore i don't pay it much attention, but i noticed lately that the exact same issue is back!

i have been upgrading to RB6   and after a while   and back to RB5.

also  i switched from Mac to Windows   (because my macbook died)

I also tried to RE-Flash firmware 1.07      (i powered off  my ddj-1000, positioned the crossfader in the exact centre position  and powered it back on   and then flashed FW 1.07 again)  but it didn't solve the problem

as i searched the pioneerdj forum, there seem to be more ddj-1000 crossfaders with this problem   even with firmware 1.07

are there any other things i can try to get the crossfader in de centre again?