"a third of the time" - have you been tracking these or is that your guesstimate? My experience with these errors are that they're used by rage quitters and exploits to end the game and prevent the loss from counting toward their stats.
If you're on the light side when 'the forces of light control the map' then it's likely they just exploited the game this same way. It's trivially easy to cause an invalid gamestate, allowing this condition to become more widespread and common.
I'd suggest GPG eject the desync'd player/replace with AI during those conditions and allow gameplay to continue.
