once the player gets muted for bad language and then gets unmuted even if they type a word what is not filtered they get muted again? 

Same here. I've had players get filtered and kicked for saying good night. Seen it in the logs. They wonder what the hell happened so they try it again. And again. Then they get kicked. It's a great plugin. But I had to pull it because of this reason.

Having the same issues, any fix on this?

Came back to check in. Anyone have a patch/couple lines of code they can post?

Its not really a bug, it depends on your configs. If you add "nig" to the blacklist list then it will kick for a player saying "good 'nig'ht". Easiest solution is to not use the kick or mute, just block out the word. Maybe a solution is for the dev to add a whitelist
Plugin is broken since the Halloween patch so probably doesn't matter now