Collectible Card Game Headquarters

Describe the Bug:
When Dosan the Falling Leaf is on the battlefield, both players can cast spells during their respective opponent's turns.

Which card did behave improperly ?
Dosan the Falling Leaf

Which update are you using?(date,name)Which type(Duel,Gauntlet,Sealed Deck)
BfZ, Duel

What exactly should be the correct behavior/interaction ?
When Dosan the Falling Leaf is on the battlefield, players can cast spells only during their own turns.

Are any other cards possibly affected by this bug ?
Grand Abolisher works fine.

Worked by responding to EVENT_MODIFY_COST_GLOBAL, but since Flags: Play Cost was unset, the event was never sent to it. Fixed that in 119edb7. Better than even chance it still won't work with the (totally redundant) codepaths for casting spells without paying their mana costs or from anywhere except their owner's hands, but those are separate bugs.