<<I've seen many patterns that have you start the cable cross on the first row - hats, sweaters, socks.... I haven't seen the result "pleat" as much as yours does, but usually it comes after a rib section, rather than garter... That may be what is causing the difference. >>
The border isn't garter stitch; it's seed stitch which I chose to do rather than the garter stitch.
Apologies - it was difficult to see that part on my screen.... Still, though, the seed stitch is a "flat" fabric like garter, but the rib will naturally have a ripply texture, so that might be the difference still in the "pleats" effect.