Collectible Card Game Headquarters

Describe the Bug:
Grand Coliseum if activated for coloured mana it produces a damage card for 1 but no life is deducted from player.

Which card did behave improperly ?
Grand Coliseum

Which update are you using?(date,name)Which type(Duel,Gauntlet,Sealed Deck)
Manalink 2016/01/15: Battle For Zendikar v2,duel

What exactly should be the correct behavior/interaction ?
Grand Coliseum

Are any other cards possibly affected by this bug ?
-

What's really weird is that a damage card graphic flashes up.

It's failing because it tries to deal damage during activation as if it were doing so during resolution. I just replaced it with the Tempest cycle of enemy painlands' implementation (Pine Barrens etc.) instead, which is more robust in other respects anyway, in 9202238.