The section background images are displaying nicely on desktop view, center center and parallax (background fixed), but on the actual mobile device the backgrounds are not showing, it is not there at all.
fixed background attachments are not liked by mobile browsers.
They burn up a lot of processing power for the continuous redraws they require.
So they disable this feature but unfortunately they also badly handle that as well – Apple devices for example will blow the image up to a huge scale, others just ignore the fixed image and some just don’t show anything.