The only ideas I have is that you were using runes of infiltration, like the previous post suggested, or you were using the desperate decoy trait. If you were to hit the opponent with an attack just after these effects procced, it would reveal you.
Now, from the footage, it doesn’t seem like you’re actually attacking the opponent. However, the cause is because you activated your heal skill, mirror. Since this reflects projectiles, it reflected the pistol attack of your opponent, striking them, which would reveal you if the stealth had just activated.
Of course, this is all contingent on you having either runes of infiltration or desperate decoy. Given the uncommon level of use of runes of infiltration, I have to guess that it is the desperate decoy trait. You’ll notice that a clone does not spawn, but that is because a clone will only spawn if you have the enemy targeted, which you did not at that point in time due to them being in stealth.
As such, it looks like the thief used the sneak attack skill (pistol #1 from stealth). The first shot of the volley hit you just before you activated mirror, which procced desperate decoy. However, since mirror then reflected the rest of the attacks in the volley, they hit the thief and immediately revealed you.
If you weren’t using desperate decoy or runes of infiltration, then I don’t have an idea.
There’s another anomaly I noticed in the video too. Around the time the thief stealthed (~9 second mark), a new “ally” dot appeared on the mini map just south of the raven capture point. This then disappeared when he opened up with an attack a moment later. I’m not really sure what the dot is, or why it would show up at that point. It does not appear to be a replacement clone because your other three are still fully visible and it wouldn’t make sense for one to spawn over there. Were the two of you in a party? Perhaps that could somehow cause that dot, or perhaps contribute to why you were revealed if you weren’t running runes of infiltration or desperate decoy.
