Why can’t my Canon 600D perform AEB?

I have a Canon 600D, it’s on firmware version 1.0.2. I am in M mode. I set AEB to take 3 photos, then go to shoot mode, and select continuous shooting.

I focus, press the shutter, and only one photo is taken. I have to press the shutter 3 times, or hold it down, in order to be able to shoot the bracketed sequence.

Another weird problem is, I can’t use the left/right arrows in the Exposure menu (not in menu, not in quick access and all I can do is create a bracket using the main dial). But the left and right arrows should do under/over exposure for me right?