it happens. it does need tweaking no doubt. But i can see why Angus Lee would regain it after winning and defending the belt after he basically held #1 for so long.
I know ive exp this in the past, even retaining #1 for 2-4 months in a row, with others not passing my fighter w/o a title with their fighters winning 2-3 efc title fights.
I do hope the ranking system can be tweaked to be more consistent.