Not sure why this happened but it should be brought to attention for Raid teams. The bug prevents players from joining a fireteam of 5 or less (as far as I have seen). Last night, me and my fireteam of friends were playing together on Crown of Sorrow. We totalled 6 players. One of our members had to go feed his dog so we sat there to wait. He timed out and got AFK kicked from the raid. He tried joining back but everytime he did join, he was immediately removed from the fireteam. We then tried it with a sherpa later that night. We had 5 members sitting in Orbit, with the Sherpa being our 6th. The sherpa tried joining but it would show him at the bottom of the list at 0 light level. While it was happening he kept telling us it would not allow him to join. We even changed fireteam leaders to see if one of us was bugged. It still did not allow him to join us. The workaround? We split up the fireteam and reformed again, letting the Sherpa join third and it seemed to let him in, to which we completed the raid.