It’s either a case of the bow being out of tiller, or, when it was made, it wasn’t tillered and the shelf cut to accommodate it properly. What you see is not unusual with older bows. Many bowyers now radius the shelf to eliminate that “look”. If you want to shoot it off the shelf, you’ll simply need to build a bump under the material. Looks like you’ll need at least 1/8”.
I usually place my nocking point at 3/8” high, then, tune from there. It seems all my bows fall from 3/8” to ½”