He was using Comon Mod Tools and Ecomanager. I used Supreme Scoreboard.
I'll see if I can post the full logs later.

Thanks. As I dont seem to be able to attach the entire logs, I post what I think are the relevant sections:

Game 13843370
warning: ACU kill detected. Rating for ranked games is now enforced.
debug: Loading module '\000/effects/empfluxwarhead/empfluxwarheadeffect01_script.lua\000'
debug: Loading module '\000/effects/empfluxwarhead/empfluxwarheadeffect02_script.lua\000'
debug: Loading module '\000/effects/empfluxwarhead/empfluxwarheadeffect03_script.lua\000'
debug: Loading module '\000/projectiles/cifempfluxwarhead03/cifempfluxwarhead03_script.lua\000'
info: Sending game result: 4 score 1
debug: Loading module '\000/lua/ui/game/gameresult.lua\000'
info: Hooked /lua/ui/game/gameresult.lua with /mods/supremescoreboard/hook/lua/ui/game/gameresult.lua
info: SSB >>> TRACE GameResults: [4] = score 1, army = Protect
info: UI_ApplySelectionSet 1
info: UI_ExpandCurrentSelection
info: Sending game result: 3 defeat -10
info: SSB >>> TRACE GameResults: [3] = defeat -10, army = Playing33
info: SSB >>> TRACE GameResults: Playing33 has been defeated by Protect
info: SSB >>> TRACE AnnounceDeath Playing33 has been defeated by Protect
debug: Loading module '\000/lua/ui/dialogs/score.lua\000'
debug: Loading module '\000/lua/ui/dialogs/hotstats.lua\000'
debug: Loading module '\000/lua/ui/dialogs/myeffecthelpers.lua\000'
info: SSB >>> TRACE OnBeat() player has died: Playing33
debug: Loading module '\000/projectiles/sinker/sinker_script.lua\000'
debug: Loading module '\000/projectiles/tdfplasma02/tdfplasma02_script.lua\000'
debug: Loading module '\000/projectiles/tdffragmentationgrenade01/tdffragmentationgrenade01_script.lua\000'
debug: Current gametime: 00:08:30
info: UI_Lua import("/lua/keymap/hotbuild.lua").buildAction("Mass")
info: UI_Lua import("/lua/keymap/hotbuild.lua").buildAction("Builders")
info: UI_Lua import("/lua/keymap/hotbuild.lua").buildAction("Sensors")
debug: Current gametime: 00:09:00

Game 13843518
debug: Loading module '\000/effects/entities/inainoeffectcontroller01/inainoeffectcontroller01_script.lua\000'
debug: Loading module '\000/lua/sim/damagearea.lua\000'
debug: Loading module '\000/projectiles/cifempfluxwarhead02/cifempfluxwarhead02_script.lua\000'
warning: ACU kill detected. Rating for ranked games is now enforced.
debug: Loading module '\000/effects/empfluxwarhead/empfluxwarheadeffect01_script.lua\000'
debug: Loading module '\000/effects/empfluxwarhead/empfluxwarheadeffect02_script.lua\000'
debug: Loading module '\000/effects/empfluxwarhead/empfluxwarheadeffect03_script.lua\000'
debug: Loading module '\000/effects/entities/sifinainostrategicmissileeffect02/sifinainostrategicmissileeffect02_script.lua\000'
debug: Loading module '\000/projectiles/cifempfluxwarhead03/cifempfluxwarhead03_script.lua\000'
info: Sending game result: 4 score 1
debug: Loading module '\000/lua/ui/game/gameresult.lua\000'
info: Hooked /lua/ui/game/gameresult.lua with /mods/supremescoreboard/hook/lua/ui/game/gameresult.lua
info: SSB >>> TRACE GameResults: [4] = score 1, army = Melo
debug: Loading module '\000/effects/entities/sifinainostrategicmissileeffect01/sifinainostrategicmissileeffect01_script.lua\000'
info: Sending game result: 3 defeat -10
info: SSB >>> TRACE GameResults: [3] = defeat -10, army = Playing33
info: SSB >>> TRACE GameResults: Playing33 has been defeated by Melo
info: SSB >>> TRACE AnnounceDeath Playing33 has been defeated by Melo
debug: Loading module '\000/lua/ui/dialogs/score.lua\000'
debug: Loading module '\000/lua/ui/dialogs/hotstats.lua\000'
debug: Loading module '\000/lua/ui/dialogs/myeffecthelpers.lua\000'
info: Sending game result: 4 defeat -10
info: SSB >>> TRACE GameResults: [4] = defeat -10, army = Melo
info: SSB >>> TRACE GameResults: Melo has been defeated by Melo
info: SSB >>> TRACE AnnounceDeath Melo has been defeated by Melo
info: SSB >>> TRACE OnBeat() player has died: Melo
info: SSB >>> TRACE OnBeat() player has died: Playing33
debug: [uiutil.lua, function UIFile()] - Unable to find file:/textures/ui/seraphim/icons/units/unknown_icon.dds
debug: Loading module '\000/effects/entities/sifinainostrategicmissileeffect04/sifinainostrategicmissileeffect04_script.lua\000'
debug: Loading module '\000/effects/entities/sifinainostrategicmissileeffect03/sifinainostrategicmissileeffect03_script.lua\000'
info: UI_ApplySelectionSet 1
debug: Current gametime: 00:13:30

Just played two 2v2 games with my mate Playing33 (#13843518 & #13843370). Both times his ACU got killed, but full share did not work. In stead his units became neutral. In the second game full share did work for the other team.

It seems like a bug that should be fixed.