To me, this looks like I am in the camera directory’s tab, since it is the same colour as the background of the open folder. But I’m not, in the 24 directory’s tab. This seems very backwards and confusing to me, and I’m always clicking to the wrong tab, making tabs completely unusable.
Nautilus uses the Tabs widget from libadwaita, which is shared among many apps, so there are some designs concepts to be developed to ensure a proper consistency.