It "saves" them in that they are persisted on the server (as best I can tell) but the sequence is

  1. POST /review/temp
  1. POST /review/temp
  # all done, submit the batch
  1. POST /review/submit <- 500 Oops we sorrwweee
  # now every comment is gone

I don't recall this second whether the actual sequence is "POST" followed by "DELETE /review/temp" meaning this is 100% a JS bug or whether it's "POST" and the controller for submit nukes the temp version, making it a ruby bug

And yes, "extremely pissed" isn't strong enough but ... put it on the list of the other 48,000 issues, I guess