Nyadriel
How do you know he is a hacker? Hm?
Don't assume.
He may have attacked you, THEN went into protection (he may even had gotten attacked at some point after he attacked you)
Actually, it does sound like a hacker. So its safe to assume so for at least invetigation. If his damage protection says anything under 23 hour and some minutes (say 17 hours) it means he's been in it for 7 hours already and UNLESS he attacked 7 hours ago or earlier, he is in fact attacking under protection.
Whether its a glitch or he's cheating or a misunderstanding, that's up to admins to find out.