They have been posting everywhere creating useless threads asking for fix or posting in original development threads of the respective roms on how to fix it.
So, here it is:
There are TWO methods to fix it:
1. Press Vol - and then Vol + after picking up the call EVERYTIME.
2. Or, you can simply install the attached file and run it ONCE, it will be activated and everytime you accept a call, it will automatically do the work
PS: I did not create this tweak, somebody else did, I'm just sharing it with you