It seems like Mirror-Dumbledore acted in accordance with exactly what Voldemort wanted to see. In fact, Mirror-Dumbledore didn't even reveal any information that Voldemort didn't already know or suspect.
Odds of Dumbledore actually being dead?
The Mirror in canon isn't limited to the viewer's knowledge (cf. the appearances of Harry's extended family); it's unlikely that the HPMOR version has been given that limitation, so fulfilling that limitation is not a strong indicator. Moreover, Quirrellmort's CEV probably is not to defeat Dumbledore, so the Mirror should not show it. I think odds are high that this was the real Dumbledore, and that he has been, not killed, but cast out of the time stream. Removed from game, if you will.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 110.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: