I think it may be a huge serve of misdirection.
Brainstorm is a massive coward, and I wouldn't put it past him to have painted the con symbol on the faceplate as a last ditch "hey wait I am one of you" effort to get out of being shot.
For the moment I am just as suspicious of rewind, though in all likelihood, whoever opened the slow time cell for the DJD was annihilated by them anyway, it's not like the DJD would really care about one Decepticon agent, or perhaps the agent was taken out by an Autobot at some point?
Anywho, it gives us a massive talking point or seven to whittle away the next month.
Looking For: Wreckers Saga TPB Collection (with Requiem)