You get the same sort of thing in film viewer as well. I believe it happens because the distance to engine noise changes? Or, just an auto "resetv" command after the swap? All I know is that it has been happening for a LONG time, even before VR. As I see it, the engine never cuts off, it just has the "engine start sound" adjusting. It makes sense to me as switching from VR to desktop could change the noise parameters? Maybe try it again, but this time un check "auto swap mode". Even turn it on, if you have it checked already. May not be the problem but doesnt hurt to check!