It's like a Freudian slip, but it's specifically when autocorrect changes what you typed to say something revealing or true.
*texting*
Person 1: Brant is so shifty.
Person 2: Shifty is a good way to describe him.
Person 1: Oh, did it autocorrect to shifty? I typed shitty... But he is shifty af.
Person 2: Hahaha autocorrect slip.