The SD suffers from the same malady. It has the later water pump pulley and the short 1000 mm belts. It's impossible to install the belts with the water pump pulley in place. I cannot figure out the issue because the belts are Continental and are exactly to spec.

I had to remove the water pump pulley..........get the belts in the groove...........and reinstall it. Then, tighten the alternator. No fun at all.

I wonder if it's a common problem with the late 617's?