Sorry sputnikshock, I don't want to be nasty, there's one thing left, you need to have manually enabled MW50 instead of WEP.
Nasty? C'mon! Let's make this as good as it gets.
I know you have a pretty profound knowledge about german piston engines.
I initially had referenced the Jumo 213A-1 + MW50 in the fm.
However, when testflying I had instant single-engine failures whenever I activated MW50. Couldn't find the problem and
therefore, as a workaround, switched to the Jumo 213A-1 1.7ata model. Which was not perfect, but worked.
I just rechecked with the MW50 variant, and found out that the engine failure occurs when applying MW50 when the engine is already running at 110%. If I apply MW50 at 100% engine power, and then increase to 110%, it seems to work fine (However, during initial testing I also had a couple of delayed failures as well, and didn't have time to recheck on those now).
Now if this is how it's supposed to be, well - pilot error - my mistake. If it's not, I'd be happy if someone could point me at the potential source of trouble here.
Thanks.