when down shifting the engine stay at 3200 rpm's until i come to a complete stop

Randomly when I push the clutch to down shift or to come to a complete stops the engine will rev way up to around 3200 rpm's and will stay high like that until the car comes to a complete stop. Once at a complete stop the engine will idle back down and run normal. (It does not matter which gear I am in). This has happened when at highway speed and when only doing 25 mph. This issue is not a consistent issue, it not an everyday occurrence or a weekly issue its very random.