Left Engine failure in flight - Why?

Flying online (great place for an engine failure!) I experienced a left engine fail tonight.  I have no clue why it failed.  I started cold and dark from the downloadable saved C+D pure flights.  Departed etc, like normal.  Carried a decreased fuel load with 20% (set in P3D) in the tips.  Here's a pic shortly after I got it restarted.  Everything looks ok.  Oil temps just slightly below the redline if you look straight on.  Maybe that was a problem though?  Are there any failures modeled in this aircraft?  Also during previous sessions I've had my engines just quit because the tip tanks get depleted.  Has anyone else seen this?

Thankfully I used the air start and got it fired up again.