My friends and I are all on iOS 8 and we're having issues where someone will respond in the same chat we've had for months and it will create a new chat for everyone else. New chats are constantly created for seemingly no reason whatsoever and we all have like 5 or 6 different group conversation windows between all of us no matter how many times we delete or coordinate to where we're only using the same one. I'm also having issues where certain chat windows only allow me to send messages as texts. Everyone in whichever group it decides to do it to has an iPhone and I'm on wifi every time. It's just really annoying because the only solution is to delete the chat completely which is a bummer because the conversations I had had been open for months and had lots of great photos in the details sections.