FireStarwIf you have any custom sound mods, for whatever reason either sv_pure or the vpk cache will cause some noise to play after your custom sounds play, and sometimes randomly. However I've only noticed this with my non hitsound sound mods (class select mostly), so if your only custom sound is a hitsound, then none of this matters probably.
This also happens to me when I play in Russian with halloween voices (which I would highly recommend doing)