Collectible Card Game Headquarters

Describe the Bug:
Forfend when cast or if AI thinks to cast it or not at times gives a parameters error.Maybe you can find what's going on.It doesn't seem to cause problems though.

bad parameters | Open

bad parameters
get_card_instance(0, -1)
0: 0x0245D818
1: 0x0241234E
2: 0x02412C78
3: 0x024290D4
4: 0x02244BD7
5: 0x00457E4A
6: 0x0246B9B5
7: 0x0241E1BD
8: 0x0241ED05
9: 0x00435A13
10: 0x004770E3
11: 0x004B361F
12: 0x0043CD3D
13: 0x004399BD
14: 0x0047902C
15: 0x004946E9
16: 0x7C80B729

Which card did behave improperly?
Forfend

Which update are you using? (date, name)Which type? (duel, gauntlet, sealed deck)
Manalink 2016/08/27: Eldritch Moon v2, duel

What exactly should be the correct behavior/interaction?
Forfend

Are any other cards possibly affected by this bug?
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I fixed an obvious mistake in AI code in commit f0c1315c and now it doesn't seem to error when AI has creatures but does if AI doesn't have creatures and human attacks.