Well I hate to be the one to tell you your system is broken but uhh...it's broken. My guild got a double Shinai drop a few months ago.
If you have more details, like the name of the server, the date it happened, etc., that can help him track it down, if he has the time to do so.
Was on Agnarr. Our old site is dead so I can't look up the exact date but it was fairly early into us clearing Time so the best I could do is say it was probably in the month of June. But I believe (not 100%) that one of the Shinais was looted by the character Xotoh if you keep those logs this long.
I checked back on 6 months of PoP in Phinigel as well as any other time logs I have had and this has never happened. I think you might be misremembering.
My guild on Agnarr has cleared potime ~20 times. Have seen ONE Cudgel of Venomous Hatred drop. Very sad.
Guild on Agnarr we've seen 2 TA's, and 2 Cudgel's in 21 clears. We have gotten 6 songblades, darkblades, and timeforged daggers.
Let's not forget that we've only seen 1 Hopebringer yet we've seen 5 Enc Serpent of Vindication's, same loot table.
Pretty sure we've seen at least 4 if not more of the SK Cudgel's also. 1 former sk isn't on the list anymore and I know at least 1 or 2 people logged in alt's to keep them rotting.
(Read in Movie trailer voice) In a world of probability and statistics, one dragon threatens the peace and stability of the entire world. It's only weakness is a 16% chance to drop 1d1 Time's Antithesis. Tim B stars in: FINAL DRAGON. Rated PG13.
We had really bad luck with that one. We got one maybe 10 clears in and didn't get another until near the end of GoD. But the god damned paladin sword dropped every god damned week.