k-x banding :(

I'm finding some strong horizontal banding in some of the images I took recently;

some rough processing in RawTherapee & resized w/ IrfanView... original photo rather underexposed... just a snapshot

In this case as you can see it seems pretty uniform through the whole image; I have other cases where it is just a portion of the image (like, just the top third) that is effected.

Searching for K-x banding briefly I didn't see much relevant stuff. Has anyone had similar experience? Is this just something that can be expected with these kinds of (far from ideal) settings?

p.s. Notice also the irritating bar that always appears along one edge of the dng files as interpreted by some raw converters (not IrfanView I notice). Hopefully that's something that will be sorted out by the software at some point.

p.p.s. I do miss a dedicated B mode on the K-x
--
Peter