How about letting them fix the mixture control first before we jump to any conclusions.
Right now, even the auto-mixture on the 109 is causing problems at altitudes above ~3000 meters. It's only shake-free if you turn CEM off.
In comparison, it's not that bad at low altitudes when everything is set correctly using CEM. If however the problem still persists after the fix, we can start arguing it to death. (And the fanboys throw sh*t at R/L pilots because they point out obvious mistakes
)