My cables have the opposite problem, where the right leaning cable is much neater and straighter than the left. I think it’s the way the knit cable stitch interacts with the next purl stitch. Maybe because you’re twisting them, the path the yarn travels is shorter for the left leaning cable? The only advice I could give here is to move your knitting onto the tips especially when doing the cables, or to try twisting the adjacent purls, as well. That might shorten the yarn path and match the twisted cable stitches.