1098s have or had a bit of a reputation for failed main bearings due to incorrect assembly in the factory. Whether the same applies to the 848 I don’t know.
The bike's 9 years old and has done about 2,500 miles. Lack of use will most likely be to blame. It is likely that condensation (ie water) in the gearbox, or bottom end, has been in contact with something for long enough to have oxidised it. A recent stint of use will have caused, most likely a bearing, to overheat and fail. Once you strip it down, let us know what has failed and remedies can then be suggested. Good luck with it.
I also wonder since the dash was showing km vs miles that perhaps someone installed a different ECU or map that was not appropriate for the bike.
Unlikely imho. Much more likely that someone was fiddling with the dash and inadvertently changed it to the km display and didn't know how to put it back.