Glitching to roof on Manhattan bridge bug

I was playing a round of breakthrough earlier and next to the park (directly across the street) There's a red building on the corner. Somehow, a team was able to get themselves up to that rooftop and was able to spawn camp us in HQ as well as have overwatch on objective Alpha which was located in the park. I ran around for a few minutes and couldn't figure out how to get up there. So therefore i;m pretty sure they somehow glitched themselves onto the roof. I have heard of this on other maps such as New Sobek City. This should be fixed if possible because it literally killed the game because they literally spawn camped us in HQ.

Thanks