Looted head class tier token from Raz at ilvl 489, then it dropped down to 486 after use
Had this happen too with tier head piece (Dreadful Decelerating Chronograph) was meant to be 502 but converted to 499
The same thing happened to me as well. Looted a 502 Zenith Decelerating Chronograph off Normal Razzy and it dropped to a 499.