How to fix the invisible friends/players bug
Step 1.) Your friends/players are invisible
Step 2.) Go to the >pause menu >hub >social & spectate
Step 3.) begin spectating your friend
Step 4.) Cycle through spectating every player in the lobby till you loop back around to your friend(s)
Step 5.) Teleport to your friend from Spectator mode
Step 6.) It should (hopefully) be fixed.
This has worked pretty consistently for me, I believe the issue is from desyncing with the lobby/server causing everyone to disappear, by doing this method you manually "re-sync" with the lobbly/server. Super bouncing out of the map may cause desync as well.
Let me know if this method worked for you and if it does upvote if that's even a thing on these forums. If it doesn't work for you, your last resort is to restart anlaki, I'm sorry GG.