I’m experiencing a strange navigation issue on my website.

I have a homepage called “bienvenue”, which contains different project categories like “reproduction”, “architecture”, etc.
When I click on “reproduction”, I correctly see all the related projects.

However, when I click the back arrow (which should lead to “bienvenue”), the content of “bienvenue” does appear, but the URL does not change. It looks like there is an overlap between “bienvenue” and “reproduction”, as if both pages are layered on top of each other.

So visually I am on “Bienvenue”, but technically I remain on “reproduction”.

How to fix this?

website: https://tropbien.ch
issue on safari and chrome