Can someone upload a video to show what happens(one of the host side one of the client side) ?

A lot of random things happened when I tried to play the online mode with a friend, we got it to work but only on some stages.

Hosting on high latency won't work at all, we both end up in a infinite sandbag now loading stage.
Sometimes the sandbag stage is frozen when you join it, you can start it by pressing start but that stops the connection from working/infinite loading again.
Sometimes both players get a stage select and sometimes only the host.
Low latency works on some stages but some stages(Final Destination) get desynced.
Random characters get changed after leaving the waiting room and loading the stage.