CLOD Sound unstable

[III/JG53_Don]

I have still the issue on Mulitplayer servers with exterior view, that I often can't hear the engine sound of other Spitfires. Even when I'm in a Spitfire myself and I switch to a friendly Spit, most of the time I just hear the sound of the wind and no engine sounds at all.
Sometimes the engine sounds are there and then the next moment they are gone again.
This happens only online and I guess also on Full Real servers. In this case it is just harder to tell as you can only hear others from your canopy. But when friendly/enemy Spits passing my view on a FR server I can't hear the engines most of the time, whereas it is definitely possible offline even with your own engine running.