Perhaps you've cut the blue illumination or saturation or luminance or whatever a little too aggressively.
Yes, lots of evenly spaced white vertical stripes in those clouds.
Can you link us to an example raw file? (You may need to use a sharing site like Dropbox.com or the like.)
After importing the CR2 file, I played with the camera calibration panel, tested with the GPU on and off, and in general I just played with the adjustment settings. Unfortunately, I cannot repro the problem in LR 2015.12 on my Win10 box.
The image from the OP looks like a pano. If it is, do the separate images show the problem?
OK, now playing with the b&w panel, moving the blue slider all the way to -100 shows the evenly-spaced white stripes.
Moving the aqua slider to +100 enhances the stripes more.
Trying a few other raw converters
ACDsee - convert to b&w, blue -100, purple -100, shows each stripe as two parallel lines instead of as a stripe.
PaintShop Pro x9 - Same as ACDsee but takes a bit more effort to see it.
From what I can tell using 3 separate raw converters, these stripes/lines are actually in the raw file. This could be a hardware problem on the Canon camera or maybe a software problem in the firmware. As a Nikon user, I don't know enough about the Canon DSLRs.