[circonian]

There may be a way to avoid the problem entirely, but this would be a simple fix.

Just handle those keys that aren't working yourself:

local function FCOGuildBankQuickSelect_HandleKeyboardEvents(self, key, hide)
...
elseif key == KEY_E then
    ZO_SelectGuildBankDialogAccept:callback()
elseif key == KEY_ALT then
    ZO_SelectGuildBankDialogCancel:callback()
end