[Northern X5M]

Yes. I have been getting the same issue.
The dealership screwed up the SSP clutch install on my original transmission and slagged it.
Got what I thought was a brand new transmission (dealer paid for), reinstalled the SSP parts and had this issue after about 3000km.
I am thinking now I got a re-manufactured transmission that maybe had problems before I got it.
I shipped the entire transmission to Kris, turns out the dealer did get the 2 snap rings mixed up.
Reinstalled the transmission, and still have the same issue.
It is a lot better now; before, the loss of fifth gear happened every time under load, after getting the transmission back from Kris, it is hit or miss if it happens.

I find that the trans is fine under WOT, it is only under partial heavy load that I get the error. What is frustrating is I now don't know when it will happen, if you are not careful you can really zing the engine to readline.