"Click" sound when the tracks change?

[MarkoSeke]

This randomly started happening recently, basically when minimized, when a song ends and it skips to the next one, it plays the "click" sound that plays when you click the next button. I don't think this was happening before, it's really annoying. Shuffle is on, repeat all is on. The plugins I have installed are Pacemaker and Lyrics plugin. Please tell me how I could fix this.