Halo CE COOP Warping

So while me and my brother were playing through Halo CE’s campaign together, and we were randomly warping to each other during the darkened portion of the first level. My younger brother says it’s a bug, bit I honestly think it’s so we can stay together. Is there a way to turn it off?

It’s not a bug and there’s no way to turn it off. No matter what the level, when any player gets to a certain point into a mission on Halo: Combat Evolved, the game will automatically teleport their co-op partner.