kibok: Your riser definitely looks skinnier through the side plate/ arrow shelf area. However, it would have to be the same width at the latches to accept the limbs, which are all standardized to the same width.
A thinner riser, side to side, would not necessarily lead to the substantial offset you see with your arrow. It would only if they didn't cut it to center to retain strength in the grip area. However, it looks like they still cut your riser to center, thus the extreme thinness of the arrow plate portion of the riser.
You can lessen the offset a little by using thinner strike plate material, and moving it forward a little. Probably not necessary though because you said the bow was already shooting well for you. It just takes a little less arrow spine for the greater offset angle so the arrow bends appropriately around the riser.
Would still be interested in seeing a picture like the one Yellow dog took to check for limb alignment. A few years ago, I was going to buy one of the newer takedowns from a fella. In examining it, I discovered it was a "narrow riser" version like yours. Strung up, the string just didn't seem to line up properly on the riser. The limbs didn't look twisted, but yet the string didn't bisect the bow like it should have. I examined that bow for more than an hour and couldn't figure out why. I didn't buy the bow as a result.
I think Yellow dog may have the answer.