It is older then LoR bug, and Crypti know about it but won't do anything. More info in my signature.
Sorry for any mistakes, english isn't my primary language.
"Dear players we have for you new useless event and only-one-map-use-divices, and much more new "content", but we can't repair glitch in chat system which make mutes on private channels permament. So deal with it and give us your remaining money."