Does your shift **** rock back and forth on the shift lever ? If so, be careful when you pull up and to the left to get it in R. That is when it will pop-off in your hand... They probably didn't cinch it down properly when they installed it on the shift lever...

It's an easy adjustment / fix... But have them do it at the dealer... Of course they'll have to look in the instructions... So it may take them a whole day... LOL