It depends on how we define the ABI. I see it as a set of client-visible invariants that they rely on. In my world, glibc changed the client's visible invariants, breaking the client. The client works on one glibc-based host, but not on another. What is this if not "a case of cross-distro glibc issues?"

Overall, both of our points of view on compatibility were discussed well in that thread; we probably shouldn't repeat ourselves. :)