Strange interaction with Hermit Yoda during Tier 3 Mythic Grand Master's Trainin

Yeah, this happenings everytime. All characters on the Mythic tier have an "invisible taunt" that disappears on taking damage. It's designed to spread the high damage of the opposing team between your characters so you don't lose one out of the gate.

This invisible taunt prevents Hermit Yoda gaining stealth, but he keeps the evasion buff as if he was stealthed.

I think it's a result of the stealth (which isn't happening visually) expiring that allows the enemy to finally hit him, and break the taunt, putting everything back to normal.