I'm currently playing on a realm, and I brought a few villiagers home to the spawn area. I had a farmer (who traded wheat, etc.) as one of them. While I was building the trading hall, I went back to check on them, and couldn't find my farmer. For some reason, I had a fletcher instead! Now, I haven't been able to recreate this in a singleplayer world yet, and I'm not sure if it's just this version, or if it's even a bug, but when I searched for something like this, nothing came up. So I'm posting it here, so that it hopefully gets fixed, cause I'm pretty sure that this isn't a feature.