Message from the player who triggered the crash: the muler with items in its trunk can be transferred to the cave successfully. The player's corpse crashed the game. Though I am not 100% sure what he means.

13403.682 Info ServerMultiplayerManager.cpp:978: updateTick(8618424) received stateChanged peerID(9) oldState(WaitingForCommandToStartSendingTickClosures) newState(InGame)
13409.737 Info ServerMultiplayerManager.cpp:1086: Disconnect notification for peer (9)
13409.738 Info ServerMultiplayerManager.cpp:978: updateTick(8618775) received stateChanged peerID(9) oldState(InGame) newState(DisconnectScheduled)
13409.738 Info ServerSynchronizer.cpp:613: nextHeartbeatSequenceNumber(790347) removing peer(9).
13412.407 Info ServerMultiplayerManager.cpp:1086: Disconnect notification for peer (8)
13412.407 Info ServerSynchronizer.cpp:613: nextHeartbeatSequenceNumber(790508) removing peer(8).
13459.881 Error MainLoop.cpp:1468: Exception at tick 8621727: The mod Player body abduction (0.3.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event player_body_abduction::on_post_entity_died (ID 153)
LuaEntity belongs to surface biome-desert_mission_platform_core_27_8 (index 8) but a LuaEntity belonging to surface biome-desert_mission_scan_cave_27_7 (index 13) was expected.
stack traceback:
[C]: in function 'draw_sprite'
player_body_abduction/control.lua:105: in function 'attempt_abdution'
player_body_abduction/control.lua:176: in function <player_body_abduction/control.lua:163>
13459.881 Error ServerMultiplayerManager.cpp:84: MultiplayerManager failed: "The mod Player body abduction (0.3.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event player_body_abduction::on_post_entity_died (ID 153)
LuaEntity belongs to surface biome-desert_mission_platform_core_27_8 (index 8) but a LuaEntity belonging to surface biome-desert_mission_scan_cave_27_7 (index 13) was expected.
stack traceback:
[C]: in function 'draw_sprite'
player_body_abduction/control.lua:105: in function 'attempt_abdution'
player_body_abduction/control.lua:176: in function <player_body_abduction/control.lua:163>"
13459.881 Info ServerMultiplayerManager.cpp:808: updateTick(8621727) changing state from(InGame) to(Failed)
13459.890 Quitting: multiplayer error.

Another related problem is, after the old mission(the 2nd core upgrade) aborted and someone dropped to a new mission, players who went offline on the old map still spawn on the old map after they rejoined the server, leaving them unable to extract.