No, it’s definitely not a preference. Lightroom has a bug where the previews are sometimes not rendered correctly until you zoom in 1:1. It looks like this is the same bug. Adobe knows about it but has not fixed it yet.
You may want to vote 'Me too' here: https://feedback.photoshop.com/photoshop_family/topics/lr-7-3-1-often-not-updating-renderi ng-in-full-res-in-develop-module
Ah... Well, at least it's just another bug, not something bizarre I was doing. I also looked at the images in Bridge, and they appeared normal there, though that doesn't help at all with what Lightroom's doing (or not doing).
I've noticed that changes in Develop often don't show in Library, but didn't connect that to what I'm seeing... May not be a big bug in the "inside Lightroom" world, but from out here in user land it's kind of annoying.
Of course it is a big bug and I have asked Adobe again to get it fixed.