Me JPG's are B+W ?

Today I thought I'd test all those features on the K7 which are sadly JPG-only: lens correction and HDR. So I shot RAW+ and then set JPG for the couple of in-camera HDR shots. It was then I noticed the preview image was monochrome.
Now back home and I can see all the JPG's are B&W while to PEF's are, of course, in colour. I've checked the camera settings and couldn't see anything wrong or anything to change in custom settings.
As I final test I've just tried a few jpg shots and they are full colour as I would expect. All I have done is change the battery which may have reset the camera.

I never use JPG so any clues to what dumb thing I could have done to set JPG to B&W ?

Sounds odd. Are you sure you hadn't been playing with the settings and set up the B/W filter by mistake?

It is possible but then I haven't subsequently turned off the b/w filter. I guess unless it happens again I won't know.

luckily you've the RAW files.
Are there some photos that looks great in B&W while you would never thought of doing that (making the photo B&W)?

Sounds like you may have activated it by mistake instead of changing focus points?

It's easy enough to do!

Yep I guess so - not something you can do if the camera is set to RAW.

Also I've just noticed that browsing the folder using windows that all the images (pef or jpg) are displayed in b&w as I assume the embedded jpg is being used...and that is B&W.