This is probably a bit of moiré-effect caused by the texture direction against your LCD screen. Some textures are affected more than others and also the details that the textures has. Try a different scale-setting and see if that helps. This issue is most apparent when zoomed out as you've noticed, but is usually fine up close.
I forgot to add that it's difficult to capture with a screen shot and much easier to see with a video. Catching something like this with a screenshot, is next to impossible and is like winning the $1 billion Power Ball lottery!
Have you adjusted the lighting conditions? I am converting an older route to TRS19 standards and have had to make 3 attempts at it so far as it became corrupted twice in the same way that you describe. I noticed that the second corruption occured right after I adjusted the lighting. So far I've got it running in TRS19 but have been very careful not to touch any of the environment settings.
This is a TRS10 route which I've brought in through TS12. Before my third attempt I made some of the necessary changes to the environment in TS12 and it seems to have worked as it is behaving in TRS19.