When we did pants fitting at the tailoring classes, we were taught that fabric creases point to the problem areas. Today's use of stretch in woven fabrics makes it easier for a greater number of body shapes to "fit" into a pair of pants, but now creasing tends to happen where the fabric is "using" the stretch to conform to the actual body shape.
The back view of these pants shows the creasing occurs in a diagonal line from the outside mid-hip to the inside upper thigh. To fit Shannon's unique body shape, the pants need a bit more fabric at these two points; right now the "extra fabric" is being supplied by the stretchiness of the fabric which pulls between these two points which leads to the creasing. If there was extra fabric at the side seam and the inner thigh, a tailor could redo the seams to provide a bit more fabric at these points and the creases would magically disappear.
Since women's ready-made pants don't provide the extra fabric (which men's pants often do--terribly unfair, in my opinion) the only way to get a perfect fit is to buy a larger size and get the pants altered. Or to buy this size and live with a less than perfect rear view. Or to hope that the fabric will eventually stretch out, and remain there, to provide that extra bit of fabric.
In a tailored pair of pants like these, you should not be able to see the back upper thigh area shape clearly through the pant. Ladies with skinny thighs rarely have this problem for obvious reasons, but those ladies with a curvier thigh and posterior often settle for a less than perfect fits because the stretchiness of the fabric makes the pant look acceptable from the front.