CDJ-900 Slip Mode Buttons light up

Hello, my apologies if this question has been asked before as I am a new owner of CDJ-900s and new to this forum. Question: How come when I press slip mode on one of my CDJs, the loop buttons and Rev button light up for a second (they flash warning me im on slip i suppose) while on my other CDJ it does not. I have see other peoples CDJ-900s do both. Thanks for the insight!!