I had two trader llamas disappear from inside a pen I made for them. They have been there since shortly after 1.14.0 was released. Relogging or restarting the game did not fix it (they weren't just invisible). The pen crosses one chunk border and is one block away from another one (see photo).

An hour or so later, the other two in the pen disappeared as well. I know initially there was some sense of a taming mechanic, has this been scrapped?