I restarted my game a few times since the new DLC came out and after a short period, I get the message saying the the mission 'undefenable' has expired and there is nothing I can do about it.
I thought the time senstive missions were all made to be visible to the player when they appear, but for some reason it does not appear for me otherwise I would had done so.
Further detail, I would had done the first Pure mission already as this was consistent across all my restarts.( I dont like missing missions and will restart my entire playthrough if so)