We knew this would probably happen, but we thought he'd passed it already. I also have a theory, or rule for life with dogs, whichever, that says that one day a month their circuits get all shorted out and they seem to forget everything they knew.
Maybe yesterday and today were those days. I hope so.
Momo turned two this past June and was starting to test boundaries gently. So I started walking him with his e-collar on again just to be able to remind him gently when he thought he'd try it again. But he seems to be struggling because he's genuinely torn between jealousy and protectiveness, and love for his little brother and a little antipathy towards me and Meg. He loves Jozsi even though his little brother's favorite after-dinner game is 'The Flying Death-Clamp' which involves leaving terra firma, mouth open, eager to make a landing on whatever piece of Momo he hits, and then sinking in his puppy fangs. Most of the time, Momo takes it all lying on his back.
So, we're going to experiment with some seperate walks and obedience training and see what that happens. It may be that two dogs and two people is actually less than the one-person-to-dog unit of measurement that you would intuitively think it might be. (And sadly, Momo doesn't seem to understand my telling him that we're going bird-hunting in 4 weeks. And that he's the star.)