Using Network theme, the custom-background does not appear on buddypress pages once buddypress is fully activated.
<body class="directory groups logged-in ">
If not activated (error 404 is only because BP is not fully activated, but is a BP page, and the custom-background carries through just fine)
<body class="logged-in error404 custom-background">
I imagine I have missed a glaring step, but have gone through everything and find nothing in the forum.
Wishing the forum would let one search only within a theme. I consistently get answers not related to the network theme even when I quote it.