Well at this point, then, I think the concern is that these bad mags don't show up in the maintenance hangar or that there is too large of a margin before they do. Given the above remark, though, maybe after changing mags that show up in yellow we should get another one or two that are still yellow or even red despite being new, hmm?
Considering the developers claimed that fluid leaks don't always show immediately in maintenance hangar after they've started (I don't know if this claim is correct or not), it'd be logical that a bad mag would not show unless the engine is started. Unless, of course an insulator is broken and shorting to ground, or there's some other visible defect.
Anyway, this bad mag thing is quite wide spread. I have like 100 and 200 rpm on Spitfire Mk Ia after 1.4 core update. I think it was the left mag that had 200 rpm. And the result is the same whether I test left or right first, thus cannot be caused by plug fouling while switching mags. And I think there's somewhat bad mag on one (or several) of my P-40 variants. Maybe I should just swap these again and again until I get proper mags. I do hope though that the faulty from the factory ratio would be toned down a bit. It's not on top of my wishlist (I think one of the biggest wish at the moment would be a better, more immersive vibration modeling - I preferred the old one over the current) but it's on it nevertheless.