I think he is actually right, nothing with Sounds or Music seems to work properly, which release of Construct 2 are you using?
I use the latest Beta 120.2, but I also had this problem long before this beta release, just haven't got around to post about it.
In my tests I actually managed to get music to stop playing by leaving the Tag empty so it effects the last played sound. But its not a workaround the problem though, since its useless if any other sound plays in between.
I currently only use .ogg files in my project, but that shouldn't matter.