Raleigh Detour IE 2019 Weird Bolt-On QR Dropouts...

I don't suppose anybody here knows the reason behind this odd dropout design? I asked Raleigh, and they didn't give me any useful info!

What we're looking at here is the tail end of a 2019 Detour IE. The spacing is 135mm, and the dropouts are slotted for a conventional 9mm quick release setup.

But if you look carefully, you'll notice the dropouts are bolted in place and removable. The right-hand dropout has a 22mm nut securing the two pieces together. The left side just uses a conical shaped insert. (If anybody is interested in seeing these in more detail, let me know and I'll take it apart again and shoot more photos.)

If the two inserts are removed, I'm left with a frame with 148mm spacing. But, oddly, the hole on the left side is 18mm diameter, while the one on the right is 16mm.

My intention was to install an Alfine di2 hub here for integration with the Shimano E6100 motor this bike is equipped with. The problem is that, once the 14mm thick dropouts and 6mm no-turn nuts are stacked, I'm left with only 5mm of threaded axle poking out on each side. I spoke with Shimano tech, and was advised that Shimano publishes no minimum thread engagement numbers, so I'm left assuming that 10mm is the minimum I can get away with.

I contacted Raleigh to basically ask what's up with these dropouts, and whether they have any alternate dropout styles available that can be bolted into place. Their answer: No, and "the Alfine may not hold up to the stress for ebike use" which is a silly thing to say considering the 2015 Raleigh Misceo IE I ride came outfitted with an Alfine hub.