If I had to guess - it's the terrain causing a momentary lack of connection in an electrical part - perhaps a fuse bouncing just enough to lose contact.
Remember - these are dual sport bikes - not trail bikes. While they can handle a lot, I doubt they are built for serious off-road shananigans and severe rocky bouncy terrain.
You might be shaking her brains just a bit too much.
Does it ever happen on paved surfaces?
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2008 WR250X
Gearing: 13t - 48t
Power Commander 5 / PC-V
Airbox Door Removed - Flapper glued - AIS removed
FmF Q4
Bridgestone Battlax BT-003rs