In 0.13.0 It seems to be duplicating the chat when a message is sent. Is there a function that I can add as a plugin to fix this?
That doesn't happen for me. Maybe it's lag or network delay? That could be it. I wouldn't recommend using a plugin to fix this issue, as if it is a network delay/lag issue, a plugin won't really help.
The duplication part comes from MCPE sending NACK too fast and RakNet not checking duplicated packet IDs.