This is a definite glitch but I’ve recently decided to call it a charm spell. It works on the undead Brute’s as well as the flesh and blood lizard man Brute’s.
You need to have a thrall or aggressive pet with you. Wait for the Brute to see you and go into it’s dog like animation where it tilt’s it’s head. Shoot it with an arrow at this point. Wait for your thrall or pet to run up and attack the Brute. If it attacks fast enough before it goes into attack mode… usually the Brute will go from a crouch to standing and then into attack mode… the Brute will be charmed (glitched) and not attack back. This has been in the game for at least 6 months.
I do all my playing and testing in Single-player. So if I fail to mention it please feel free to assume I’m referring to the single player game.