The best general fix is to not use murmur or other externals, but to use another FXServer on a separate port and host it off of that.
Murmur reportedly has some incompatibility issues (Which you can see above) which leads to it having high packet loss among other things.
Just set up another FXServer on another port and use it as your mumble server, the mumble port will be the same as whatever you set your FXServer to. If you want to auto-generate the channels just add pma-voice to the server and do setr voice_externalDisallowJoin 1 (which just kicks anyone who tries to join the server)