Yes, this. We had actually worked together amicably for several years, he as senior, I as mid-level. Then we both got bumped up. As part of my new responsibilities as senior, I tried to surface issues and confront them transparently. I was mindful not to point fingers or show anyone up but rather identify them as shortcomings in our practices or policies.

For cultural reasons, I think he felt threatened by this and assumed it was his responsibility to hide issues and save his own face. It fell apart pretty quickly. It sucked but I've used it as a career lesson.