Weird lag/stutter at around 3k revs
 

Recently in my 5AT I've noticed at around 3k revs I'll get a weird stutter in power only for a second maybe and then it'll keep climbing the revs with no power loss what so ever, but I've only really noticed it in 4th and 5th gear. Also I've noticed If I get 3k revs in 4th or 5th and let off the gas it'll decrease revs fine but at about 2.8k it'll do a sharp decline in revs down to maybe 2.5-2.6k, not really sure what this could be. I haven't got any tunes or engine mods at all. Any help on the matter is appreciated as I'd like to know what could be causing it