2013 manual... I got this the first time at about the same milage.
FWIW, I have to really be sure I've *put* it in Reverse with a nice "chunk". Sometimes you'll think you have but it's only partially engaged (at least that's my interpretation of what you felt). At 36k miles I've been putting it in Reverse twice or three times as an OCD tick.
Sucks that it lost my trust, but we have an understanding now. :rolleyes2:
This has nothing to do with your post, but I figured I'd mention it. I had trouble stalling Reverse for months because I didn't understand the gearing. Turns out Reverse isn't the lowest gear. The ratio of Reverse actually falls between First and Second. So now I treat it more like 2nd gear, I find myself in better stead.