It seems Cryptsy has changed their timezone again.

--UPDATE--
The API returns nothing for drkbtc and others pairs. It should not be timezone issue. at least dogebtc works though it returns glitch data  some time.
DOGE/BTC and DRK/BTC uses same entry. that's quite strange for DOGE/BTC works but DRK/BTC does not work totally.

--UPDATE at 15:55 GMT --
The time must be broken once. The repeated trades is found obviously in some cold market such as VTC/BTC QRK/BTC.
I see.
The last trade is in the future with incorrect date. For example, the last trade of DRK/BTC in our database is 2014-05-24 03:19 GMT. All trades is ignored before 2014-05-24 03:19, so the trades is not refreshed anymore.