i'm able to store counterfeit pardon edict and leniency edict in the bank, but something is wrong with grand amnesty edict, i'm unable to store it in my own bank.
To be fair, that particular item seems like something you'd want to have in your inventory rather than the bank. After all, if you need to use it, you'd probably want to avoid entering a bank in the first place...
It's not a bug; they mentioned in the last ESO Live that it was intended that way, 'cause it's supposed to be a special reward.
A largely useless special reward, considering even after grinding the mass murderer achievement the max bounty I've managed to amass was like 14,000 gold XD