Semmelrocc
E*POWAH Master
I had the exact same thing on my bike last week. Just have to check the bolts every now and then, especially when you hear an unusual rattle.I cleaned the bike just before my last trip and I noticed that the rear caliper was moving!
Both bolts were loose!!!!
I absolutely could not tell when using the bike, before or after I tightened the caliper bolts.
PS: The front was OK.