I believe that the Auror trio was memory charmed.

There was a distinct body-hitting-the-ground-with-a-thuddish sort of sound.

"Thank you for taking care of that, Quirinus," said Dumbledore to Professor Quirrell, who was now standing above and behind the unconscious forms of the three Aurors. "I confess I am still feeling a bit peaky. Though I shall handle the Memory Charms myself."

-Chapter 46

However, both McGonagall and Snape know that Harry has developed a charm which can affect the behavior of Dementors:

Albus nodded grimly. "Unfortunately there is now another wizard who laughs at impossibilities. A wizard who, not long ago, developed a new and powerful Charm which could have blinded the Dementors to Bellatrix Black's escape.

-Chapter 61