For about 3 months now, we've been observing flurries of timeouts on various PlayFab calls, almost always on Xbox (in the form of ERROR_WINHTTP_TIMEOUT 12002 errors). This usually happens on the login call, but that could just be because that's the first PlayFab call we make in a session. Playstation and Steam seem to be largely unaffected.
This started happening on various titles, including one that has already been released for almost a year, which makes it seem like a PlayFab infrastructure issue. It's most prevalent in a title currently in development, with no live users using the xbox login pathway, so it seems unlikely to be an issue with the load from a particular one of our games. However, the problem does come and go - sometimes it barely happens, and sometimes it happens more often than not.