Messages vanished into the ether

[AzrealNoctis]

When I got my replacement phone (OnePlus 7 pro) and transferred everything over, for some reason, I noticed that my group chats had gotten all sorts of screwed up. For example, I have a group chat with three of my friends and in said group chat, only the things I sent are there, and the stuff they sent me is now in their conversation, this happened a while ago so I'm not too torn up about it, but would still like to know why my messages decided to play digital 15 puzzle, also some of the old messages repeated themselves. The first image, (sent by assassin) is something he said in the group chat after my wisdom teeth got removed. The second image is where that text should have been. The third is just an example of the duplicate messages.