After some on Stream Testing (W4stedspace)
one of the guys was unable to join the game after the earlier gameplay.
the problem seems to be with the amount of content being updated while the player joins.
im a network proggramer for a couple games so id guess something along the lines of, as the player joins the game to many updates are happing which causes the network buffer to overflow and the game to crash.
only thing i could think of would be to pause the game Factorio style while the player joins and loads the map.
they where able to fix the problem by turning of their factory and waiting for most things to stop moving and updating.
Great game Guys!!!