Last night I happened to still be up when the infernal DST switch hit. Major issues with the DIR-625 and being set to roll back automatically.
1) Internal cabled network ping times went from 1ms to well over 500ms, but sniffer showed no traffic
2) External traffic dropped to near nil - the router wasn't passing the packets
3) I tried powercycling the router three times. The first time, internal pings to the router dropped to 0, but quickly ramped back up. The second, I disabled SPI, got no changes.
When I powercycled the third time, the router lost all configuration data entirely - it reverted to factory defaults. Once set back up by hand it works just fine.
Everything still seems to be normal at this point - but it leads me to believe that with full logging turned on (which also got lost when it reset) automatic time changes aren't handled well on this unit with 1.09 firmware.