Wrong button style, pathbar.
I love the new Nautilus pathbar, but there is a visual bug. If you open a new window, the pathbar uses the wrong style of button, but if you deselect the window and then select it again, the correct button style is restored. See attached images.
Open a new Nautilus window (wrong button style):
Open a second Nautilus window (still wrong button style):
Select the first window (correct button style):
Select the second window (correct button style):
Fedora 30 beta, GNOME 3.32.1.