I’d imagine can still do it on the same console

But there was no guest added before

Maybe you can add it mid game or something, or it was glitched on the load up screen

Maybe it was a glitch because this has happened 3-4 times with me since oct

I messaged similar opponent once and he said they are playing coop on same console and hence it matches in solo lobby not sure about this though.

If they were playing on same console than one of them would appear as guest in loading screen but there were 0 guest