I started to post a new thread but I believe this is related as well, not sure.
The OE apparently has a hard coded 512x512 pixel limit for the normal map per mile, as I said, not sure. With a 1024 texture, it is creating all sorts of anomalies, the _CL and _EV htx files are not built/rebuilt. And when using a 512 normal map with 1024 diffuse etc., well, things get pretty ugly as you can see in the attached orthos.
I'm using 1024 textures for the square tile object. Using the same software and export settings, a 1024 texture won't work but if I downscale it to 512, at least something can be built.
The clutter mask can't be put right but now that I know what's happening, maybe I can move on to recovering the lighting and detail again.
It's been frustrating the last two months, but I finally figured out what was wrong.
Back to the OP, pictures tell the story. Before, a second try would slide the entire ortho off screen but I didn't try it this morning.
Here's the ortho with 512 textures, what it's supposed to look like.
And here it is with 1024 textures!