Yeah, well, now that ive been thinking about it, i think one of my errors is that i have kinda allowed the rogue to take 2 bonus actions.
Meaning, often times the rogue will move, attack, and then as a bonus action use Cunning Action to dash and run behind a boulder or go around the corner AND THEN make a hide check as well, since he is no longer in view of the monsters. It kind of makes sense to naturally allow that, but i've never really scrutinized it like i am doing now.
The logical question in this scenario is that if the rogue is going to use his bonus action to dash away behind something, i believe he is allowed to have cover, but not necessarily be hidden, therby no longer needing a Perception check