Clicking Noise When Braking in Reverse — Is This Normal

The pads do move. They have 'ears' that are held loosely in channels in the caliper bracket, so they can move toward the rotor and away. Being held loosely, they can also move a tiny bit in whichever direction the rotor is turning when they meet it.

They are held in "support plates" (a/k/a the "fitting kit"), little springy clips that fit in the bracket channels, and the pads fit into them.

Describing earlier generations (I haven't worked on a 2023's brakes, but expect this is similar), if you look at a set of those "support plates", they aren't all identical. They are pairs, where one of each pair has a longer bent tab sticking out. When you're careful to install them as the picture shows, the longer tab works like a spring and holds the pads pushed in the direction the rotor turns moving forward. That way when you brake moving forward (which is, after all, most of your braking), the pads are already as far that way as they can go, so there is no click.

When you brake while moving in reverse, the pads therefore have a little room to travel the other way, and make a click.

Ordinarily, as time passes and things get dirtier / stickier / rustier, that nice reverse click gets a little softer, or maybe stops being heard at all. If you're hearing it nice and clearly, it suggests your brakes are clean and moving nicely, as if they were recently worked on, or if they weren't, have at least been staying in a nice free-moving condition.

 

I would clesn and the caliper slide pins to see if they are sticking. If the outer and inner pad have worn to different remaining thicknesses, it would be a clear indicator of sticking slide pins.