Hi Everybody ,
Just to contribute has this problem , i have similar bug with my MBP 15 " retina late 2013 under various OS since to Maverick to the last Yosemite 10.10.4 including bêtas ..
My problem is little different , will be occur when are using one external Bluetooth mouse (Logitech with CCC updated drivers) in Safari . If i scrolling and mooving the mouse in the same time in the browser , the bug appear and crash only the Keyboard and the trackpad.. OS X continue running and external trackpad are in use (not internal).. very strange bug..
No crash events are created in crashlog system..
I have tried different settings for the mouse and accessibility options .. always same problem.
The solution for me , is forcing to reboot with the start button..
Sorry for my poor english
Thanks for helping