Friends' world does not show up in Friends tab

Me and my friends has been playing together on a private server, i.e. one of his world we others join. I play on Windows 10 edition while the others play on PS4. Sometimes his world does not show up under the friends tab, even though i just played on his world. This just happened, I left his world, he did not log out and nothing was changed anywhere, but the world did not show up. I had this issue before, and it required an update for the host of the world to be completed, and i just updated to 1.16.201 and played on his world. He is also playing on this exact same version of the game, but it still does not work. This happened in version 1.16.200 as well.

What is strange is that it works just fine at first, but then fails. We have checked that we have linked our Microsoft accounts and that we are friends, and the others are still able to play on his world, proving that the world is joinable fron a non-LAN source. Please help!