Not unusual for these smaller guys to move up as they get a bit older. Look at Roberto Duran when he started boxing, 4 of his first 5 fights were fought at under 120 lbs. and he fought as high as 174 lbs. near the end of his career.Naoya Inoue is vacating his belts at bantamweight and moving up to super bantamweight.
Look out super bantamweight and this obviously creates opportunities at bantamweight for the contenders.
Inoue will carry his power for 3-4 more weight classes is how I see it if he decides to go up in weight a few more times during his career.