I found the log from the second Coram crash.
neo-anterior.log contains a full exception at the point the game exited:
java.lang.NullPointerException:
Cannot invoke "forge.game.zone.Zone.isCardAddedThisTurn(...)"
because the return value of "forge.game.card.Card.getZone()" is null
The stack then goes through CardProperty.cardHasProperty,
SpellAbilityRestriction.checkZoneRestrictions / canPlay,
Spell.canPlay,
Card.getAllPossibleAbilities,
and AvailableActions.
This was the game where Henzie was actually my commander and Coram was one of the 99. I drew Coram, put him onto the battlefield, attacked with him, his mill trigger resolved, and then the game failed as combat advanced.
That seems potentially significant because Coram specifically creates permission to play cards from graveyards that were put there from libraries that turn, and the exception is occurring while the engine is checking whether a card was added to a zone this turn and whether it can be played.
I can send you both neo.log and neo-anterior.log. The exception is in neo-anterior.log.
Can I attach files to these replies?
In answer to your Coram question... I have attacked with him twice and it happened both times. In both cases I did look through the discards after everyone milled, then attacked, then the game exited.