I'm seeing invalid game error for pages I know to exist. 

foobarproj by ObscurelyMeGaming (itch.io)

foobarproj is the name of the game and for my butler command I'm running

butler push ./release obscurelymegaming/foobarproj:osx-alpha --userversion 0.0.1

I see the following error immediately after

creating build on remote server: itch.io API error (400): /wharf/builds: invalid game

So I do have an answer for this. Apparently the 400 invalid game error isn't always accurate. I think my butler creds were expired on the machine I was running commands on. Once I logged back in, status and push commands worked again.

This worked for me. Thanks!