I have occasional color banding that shows up in the develop module but not in Library, nor in my windows file viewer. Shooting .nef files. when I export from either module, the bands show up in the jpeg, making the image
unusable. My external editing is Srgb. If I open the image straight from PSCC, the bands appear also. When I view in windows file viewer, there are no bands.
Check your RAM, hard drive, cables, card readers, card - it's one of them.
You don't see this in other software because most viewers - and Lr's Library, initially - just display the embedded jpeg; and Lr stresses hardware more than other software, especially during export (which is resource-intensive), hence it appearing in the exports.
Search the site for "image corruption" - comes up a lot.
For me, the problem was a dying destination hard drive...