Hello. I'm not sure if this is the right forum to post this, as it's more software-related.
Almost all dark apps have this problem, and I guess it has to do with the Android framework modifications the developer team has made, because it doesn't occur on other phones (as shown in the second album). The divider in question is likely android.R.attr.listDivider.
This is a small but noticeable bug, and I'm quite sure the fix is an easy one.