4 Design Patterns That Violate “Back” Button Expectations – 59% of Sites Get It Wrong - Articles - Baymard Institute
Some interesting research in here around user expecations with the back button:
Generally, we’ve observed that if a new view is sufficiently different visually, or if a new view conceptually feels like a new page, it will be perceived as one — regardless of whether it technically is a new page or not. This has consequences for how a site should handle common product-finding and -exploration elements like overlays, filtering, and sorting. For example, if users click a link and 70% of the view changes to something new, most will perceive this to be a new page, even if it’s technically still the same page, just with a new view loaded in.