Edder's second chance from his armor didn't trigger once I was down and still had 3 turns to before Berath's Challenge would do me in the starting area. There was no other NPC in the party at this stage.

Once he was down I got greeted with the defeat message, there is nothing he could have done but it seemed a bit premature. 

Hey Bronsteijn,

 

I'm sorry you have been having trouble with Second Chance in Turn-Based Mode.  Would you happen to have a save file where this is occurring that we could use for testing purposes?  If needed, you can find instructions on how to obtain your saves here.  if you could send the save to me at support@obsidian.net along with a link to this thread as a reference, that would be amazing.

 

Thank you and sorry for the inconvenience this is causing your playthrough.