Sorry if this is not an issue with your plugin.
Today a player joined and sometimes when he send messages they where malformed. The current format is "[N] playername: message" without the <> from vanilla. For some reason some of his messages (2 to be exact both of them only saying ":p") appeared with the two brackets.
I'm running paperspigot build 332 with luckperms, vault, vault chat formatter.
[Tue, 2. Jun 2020 18:41:29 CEST INFO] [N] redacted3: bye cruel world
[Tue, 2. Jun 2020 18:41:23 CEST ERROR] Could not pass event AsyncPlayerChatEvent to ChatEx v2.5.2
[Tue, 2. Jun 2020 18:41:23 CEST INFO] <[N] redacted3> :p