No, it's not normal! If it's an FSX bug, why don't I get it? I haven't renamed any files and I've now tried all of my aircraft, default and payware, and none of them have this problem. Is there a particular area that you get this in? By definition, an FSX bug would affect everyone and it obviously doesn't.

You have to fly in certain conditions to see it

I have seen this happen during beta tests , it turned out that when ASN was enabled there was a mystery mist  , when the tester turned off ASN that stopped .

 

Do you have ASN ?

Yes, I have ASN but it was doing it before ASN.

I will try to remane that third file.

And it only does it when the runway is wet.

You have to fly in certain conditions to see it

What are the required conditions? Anything I've tried so far that has spray/mist during takeoff does not have it once clear of the runway.

 

I have seen this happen during beta tests , it turned out that when ASN was enabled there was a mystery mist  , when the tester turned off ASN that stopped .

I use ASN but don't have the problem.

It is not ASN or anything else, just rename "fx_SnowEngineWash.fx" to "fx_SnowEngineWash.fx.off". Simple  

 

​For those of you who haven't experienced it yet, the conditions have to be just right.