Diablo Torment bug

[sergio_cannabis]

Just killed diablo on torment with my mage.
but something strange happened:

i almost killed him and then he reappeared with full health and the strange "mumbling sound" got played. i had to kill him "again" but this time his attacks were really weak...dont know what that was

[Ugily]

Likely you ran out of time on the Map of Stars, then Diablo reset himself. You then just got lucky and still kicked his ass.

[daiy]

I've had this happen to me on Nightmare I think it was, and it definitely wasn't because I ran out of time on the map of stars. I still had a good 30+ minutes. And Diablo didn't receive any affixes, and as OP said, his attacks were super weak. Gotta be a bug.

PS grats on the torment win