Desynchronization occurred in 0.1.23 of Mining Space Industries II until Treeees was disabled. Discrepancy appeared to be found in the <emissions-per-tick> section of the game state files reported in heavy mode.

Hi, thanks for the report.

Not sure what the problem is, because emissions-per-tick isn't touched by this mod.

Could you please add your factorio version and a log or stacktrace or more detailed information on the problem?

Apologies, I'm probably way off on the emissions-per-tick thing. Still relatively new to factorio mods. Hope the information below is helpful:

Factorio version: 1.1.6 (build 57355, win64, steam)

log.txt:
651.593 Checksum for script aai-industry/control.lua: 2643299297
651.594 Checksum for script aai-signal-transmission/control.lua: 2254468846
651.595 Checksum for script Bottleneck/control.lua: 3248915822
651.597 Checksum for script grappling-gun/control.lua: 3254250820
651.599 Checksum for script informatron/control.lua: 1487919689
651.601 Checksum for script jetpack/control.lua: 233632532
651.602 Checksum for script robot_attrition/control.lua: 2638208818
651.606 Checksum for script RPGsystem/control.lua: 130776113
651.606 Checksum for script space-exploration-graphics/control.lua: 17466373
651.608 Checksum for script Trees/control.lua: 2033556306
651.609 Checksum for script Cold_biters/control.lua: 307353640
651.695 Checksum for script space-exploration/control.lua: 1868719520
651.695 Checksum for script Explosive_biters/control.lua: 2672598463
651.698 Checksum for script Rocket-Silo-Construction/control.lua: 1217605745
651.709 Checksum for script Mining-Space-Industries-II/control.lua: 2011347173
651.955 Info ClientMultiplayerManager.cpp:586: UpdateTick(5870938) changing state from(ConnectedLoadingMap) to(TryingToCatchUp)
654.040 Info ClientMultiplayerManager.cpp:586: UpdateTick(5872305) changing state from(TryingToCatchUp) to(WaitingForCommandToStartSendingTickClosures)
654.170 Info ClientMultiplayerManager.cpp:586: UpdateTick(5872305) changing state from(WaitingForCommandToStartSendingTickClosures) to(InGame)
654.369 Info GameActionHandler.cpp:4965: UpdateTick (5872317) processed PlayerJoinGame peerID(2) playerIndex(1) mode(connect)
657.870 Info ClientSynchronizer.cpp:331: Latency changed to (254)
668.119 Info ClientSynchronizer.cpp:331: Latency changed to (15)
673.735 Info ClientSynchronizer.cpp:331: Latency changed to (11)
681.436 Error GameActionHandler.cpp:3520: Multiplayer desynchronisation: crc test (heuristic) failed for crcTick(5873857) serverCRC(3026470167) localCRC(1648314882)
681.437 Info ClientMultiplayerManager.cpp:586: UpdateTick(5873858) changing state from(InGame) to(DesyncedWaitingForMap)
681.570 Info ClientMultiplayerManager.cpp:757: updateTick(5873866) received player (2) desynced

Congratulations, you found a bug in factorio :P

Let's see what happens ...

Fixed for 1.1.7: https://forums.factorio.com/93542 - Tree's progress was saved and loaded, however there is emissions-per-tick value on a chunk that is not saved and is deduced from tree's progress when loading. Issue was that writing to tree_stage_index was not updating emissions-per-tick for a chunk tree is on which causes the desync because after this value was changed, newly joining client would compute different value of emissions-per-tick during load.

since factorio 1.1.7 is out, I reenabled tree aging for multiplayer in version 4.3.0