I wanted to be clear about something. For Realms, the second player inventory is NOT lost entirely. If the second player logs in first or solo, they have all their stuff, levels, etc... We flip flopped accounts and it's only when you log in second that your stuff appears missing and you are in the wrong place. This does not appear to be the same bug as originally reported. The only good news is that maybe all the stuff isn't gone permanently. I have no idea how this works on locally saved worlds though as there is no way to test logging in first vs. second.
XB1: Found out yesterday mob farms no longer work after building one for 5 hours, and so far I'm not seeing any solutions, other than finding a spawner and building a grinder around it.
I got this one too starting today 3/15. I tried reloading my owned skin, logged off and when I logged back on, it was gone again.