I work in IT consulting. For us, whenever our PMs stall the clients with: "We're waiting on an action plan" it is code for: "The only guy who knows whats going on on this project is MIA and we cannot reach him on the phone. Hang tight till we can find someone who has a clue".
Don't be ridiculous. They're working on Sunday because they didn't do a good job of fixing these issues during normal work time. There is nothing to be grateful for. They're in a business of developing and delivering a high quality work product, which requires overtime work and around the clock support.