Did you previously remove your axle (i.e. removed wheel, changed sprocket, etc..)?
If so, what I learned specific to the AGB27 model is that there is a proper sequence to the 3 metal spacers and putting them back in the wrong order of thickness will affect brake disc alignment to the pads.
Otherwise, I cant see what else other than opening up the calipers to fit in the new pads can be reason for the pads to continue to be in contact.