buzzing vibration through footpegs

just noticed a high'ish-frequency buzzing vibration through the footpegs of my 5th gen. It happens around 4k RPM and when higher up the rev range. I'm not sure whether it is me who has just started to notice it (now I'm more accustomed to the bike) or whether 'something has happened' mechanically. I did a track day a couple of weeks ago (novice only) but nothing else out of the ordinary, and no changes made to the bike. Grateful for any advice on what to check, or whether this is relatively normal for a 5th gen. Many thanks

 

It's 'normal' on a 3rd gen. They even tried adding some weights behind the footrest bracket to damp it out.