S3 Holding Revs when Clutch Pressed

[HansfishS3]

Hi all, sometimes when I'm coming to a stop and the clutch is pressed the revs dont drop immediately and hold themselves for a few seconds. This has only happened a few times within the past year but was wondering if it's normal? Anyone else experienced this? I've had my PCV valve changed

 

[LEE69]

If there is a clutch switch, change it, or scan with vcds to be certain

 

[a3 turbp]

I'd be interested in this as my car also does this occasionally