I also had some strange things with this settings, and as my movies are all french or english audio only, I changed now to: "fre:fre|f,eng,fre" and it works better.
So the "*" doesn't seemed to work properly, or maybe it works now with latest SAF version but I have not tested it.
Of course if the audio or subtitles are not tagged correctly, it can not work properly.
OK. My movies can be in many different languages so I kinda needed to use a wildcard, but if * is going to turn on subs even when the language is english, I guess that's better than not having the subs turn on when needed, so I'll just put up with turning them off manually if necessary.