You seem to be hitting all those unusual situations that should never happen!

This problem is due the xhdr function not being able to determine the date from the message header. I have added a fix for this.
The other thing you uncovered was the '(none)' in the refs column. This means the message had no references and is a thread starter so there is no need to put it in the refs table as it is already in the thread table. It wasn't doing any harm but it was wasting space.
regards
PAJ
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the latest version of this hack is always in the post of this thread