Hmm, I accidentally turned debug on in the newer version, which kind of helps here. Look in your SM log directory for l4dunscrambler.log, but it might be kind of big. Snip it so it only contains the games in question and gzip/whatever it up. If you can send the server logs for the same games, it might help, too, if there's nothing in them you wouldn't want me to see.
Updated the first post to turn off debug by default.
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