I ran into this about 20 years ago on some Volvo pads.

I was told that the thickness differed with the caliper and that varied with the market the car was sold in. The pads were from Germany and were made to fit the thickest application.

The correct way to fit them was to sand them down until they fit. So I did.

And they worked great.

I also ran into this on some Porsche 911 pads. Same situation, same solution.