It dose appear very strange especially given the fact he only lost 0.3lbs in the second attempt, Either he killed himself to make the weight the first time and thus has nothing left to loose, or hes not even trying. He didn't look drained either so its indeed a very strange one, Given it will cost him his title and some of his purse it makes very little sense at all.
But he will be paid well regardless, if the weight is an issue and turns out to be an advantage then Concepcion will walk away with a win in a fight he was an underdog in and probably get another shot somewhere else.