I call BS that he's walking around at 170lbs.
He's pretty clearly dehydrated and lean on the scale
He would be an enormous lightweight, look how much larger he is compared to Conor in every photo of them. Arguably he's a good candidate for a 165lbs division.
He definitely didn't drop a decision to Rick Story because he was too small. Maia is a huge welterweight and surely bigger then him, but the problem was clearly being out classed on the mat. He doesn't have the counter wrestling or striking like all the other wrestlers who beat Maia.
Leon Edwards is most definitely a bigger guy and on the upper end of the size range for the division. Same deal though, he was out classed, it wasn't that he looked too small or under powered. No shame in it because Leon is legitimately one of the best in the world.