I have a Nokia 6 (TA-1021) running Android 7.1.1 and
there is a bug where dark-themed apps have black list
dividers instead of white ones.
Almost all of the apps have this problem, so I believe it's not app-specific: https://imgur.com/a/yBVEd
See here for images of the same apps running on different devices and Android versions, where the dividers are white as they're supposed to be: https://imgur.com/a/5B1nD
I suppose it's because of some Android framework changes Nokia introduced in the software, android.R.attr.listDivider in particular. It'd be great if this bug could this be fixed in an update.