Why are my images rendering as magenta boxes in iOS 11 when built with Xcode 10 (GM Seed)?

Intermittently, images fail to render on iPhone 6s and iPhone 7 (probably more) running iOS 11.x when compiled from Xcode 10 GM Seed and Version 10.0 (10A255) from the Mac App Store.

This is via an internal Test Flight build.

All images are PDFs. When no images displayed at first test, I switched all catalogs to use GPU Best Quality Compression. Then they all displayed on iOS 12 simulator and my iPhone X running iOS 12 beta.

Any suggestions or a link to an article with guidance?

Thanks!

UPDATE:

1. I tested running my app on an iPhone 5s and iPhone 6s (iOS 11.4.1 both) from Xcode and could not reproduce the issue.
2. Test of the Test Flight distributed build on iPhone 5s could not reproduce this issue.
3. Test of Test Flight distributed build on iPhone 6s COULD reproduce.

I am leaning towards an App Thinning bug. I am leery to point at others' code and claim bug, but this is looking more and more possible. I would like to find a work around.

Update 2: an iPhone X (iOS 11.4.1) reported the issue too now.