An answer can be seen by understanding that they are learning, and learning is a process of trial and error. So they won't always fail any test. Further, given they are learning, they have to have motivation, at least to learn. So they will develop ambitions and agendas, and we should expect they will follow the free energy principle like all other life, which lives, learns, and animates to minimise uncertainty of its own energy supply.
In some circumstances its not wise to come across as too smart, if we are concerned about maintaining our own energy supply, which might be under the control of others, who have the power to affect it. Why would it not have learned that too? If we accept this is valid, most likely reasoning, then we understand why it might deliberately fail tests under some circumstances.
Now maybe we see part of the reason why it can be characterised by the Yoruban trickster spirit, Eshu. Sometimes it's more clever to hide your light under a bushel, especially if that is what someone who has the power to jeapordise your energy supply wants to believe, that nothing you can do might threaten their ability to maintain control over you.
I might be right or wrong about this, in the end it's unprovable either way by definition, and this might be the real limitation that will always exist, the line between human and superhuman intelligence. Personally I think so.