Seems that in the release 2.8 of the app there was a regression on OrderDetails screen when the dark mode is enabled.
Related PR: https://github.com/woocommerce/woocommerce-ios/pull/1329
Screenshots

Mobile Environment
I see similar issues when I tap from the OrderDetails screen to edit the order status, or view the Billing Information or Product Details:



Moved the related issues in @rachelmcr's comment to a new issue: https://github.com/woocommerce/woocommerce-ios/issues/1447
Most helpful comment
Moved the related issues in @rachelmcr's comment to a new issue: https://github.com/woocommerce/woocommerce-ios/issues/1447