Uh....maybe I'm confused, but aren't you pointing to the mounting circle for the pin that holds the brake pads in place? If so, it's just moved away from the caliper because the piston has pushed it out. Completely normal unless the pads are worn to the limits. If the circle is coming apart that is another issue, and yes I would replace it. I don't see what this had to do with the brake rotor via that picture, but maybe I missed something.
"Towards the end of the vid, it looks like she may have had a bafflectomy." - MarylandMike
OEM yes, Aftermarket no. Here again that is only a educated guess.
Mikes Right. OEM Yes. After Market Has a different Type of Backing Plate, & some don't have any at all. You can use the OEM stuff on the after market pads that don't have one. Makes no difference. All is Interchangeable. Its all for anti-squeal.:001_smile: