Snoke somehow forgets to read her mind to get the information he’s been seeking for years. It just doesn’t make sense. There’s no denying it.
However, let’s not pretend these same contrivances exist in the OT, because they don’t. You want to point to a similar contrivance in the OT, please give it your best shot.
Vader also “somehow forgets” to read the mind of Captain Antilles, the captured Rebel Troopers and Princess Leia to find out where the Death Star plans are and where the hidden Rebel base is. There you go, a similar contrivance just as you asked for. Now please stop being such a pedantic killjoy!