Collectible Card Game Headquarters

Describe the Bug:
- Stalking Assassin tap ability is only available when there is at least one creature tapped, else only the destroy tapped creature ability will activate
- If there is at least one creature tapped and enough mana for his 2 abilities, game show the windows choice but any choice will result in destroy tapped creature or a non/tapped error

Which card did behave improperly ?
Stalking Assassin

Which update are you using?(date,name)Which type(Duel,Gauntlet,Sealed Deck)
OoAv2

What exactly should be the correct behavior/interaction ?
- Stalking Assassin tap ability is available any time
- Window choices correctly assign abilities

Are any other cards possibly affected by this bug ?
-

The costs don't match their abilities A-B
B-A

Rewritten in ed66856.