[BUG] Rcon seems not executing forge mod commands

[Serious07]

Problem
After sending command on server by using rcon client it drop error, and don't execute command.

To Reproduce
Steps to reproduce the behavior:

1. Setup rcon with password on server, turn it on in config
2. Add on server forge mod that use any command
3. Start server
4. Try to send rcon command on server

Expected behavior
Command will execute on server correctly.

Logs
https://gist.github.com/Serious07/4f4ddfadb54f615a71f52be4171e00eb

Additional context
This bug exists on Thermos too.

Environment (please complete the following information):

• Crucible Version: 5.4
• Plugins: PermissionEx, ProtocolLib, TCPShield, Crucible_Server
• Mods: any forge mod that can execute command from console
• Java Version:
  openjdk version "1.8.0_265"
  OpenJDK Runtime Environment (AdoptOpenJDK)(build 1.8.0_265-b01)
  OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.265-b01, mixed mode)
• OS: Debian 8