Back buttons on subview (panel mode / tablet dashboard)

Quick question about a tablet dashboard and back buttons:

I have a dashboard in panel view on the wall. On this dashboard I use some buttons to navigate to other subviews on other dashboards (main dashboard for phone and such).
When I navigate to this very subview (e.g. rollershutters), I see a back button and can navigate back to the tablet dashboard.
Because I need some specific views for the tablet I also created subviews on this main panel view (e.g. garden shed with camera and door sensor / lock).
When I navigate there from a specific button, I also see the back buttons on my browser (Chrome and Edge), but not on the tablet.

However, if I migrate the subview to my main (phone) dashboard as a subview as well (same raw code) and link the navigate button to this one, the back buttons show up.

I thought, that it might be the “global” panel mode on the tablet view (and subviews), so I removed temporarily the panel mode, but this does not change anything.

So, I don’t get the reason, why the back buttons work on the same code as subview somewhere else but not on the very tablet view.

I use the subview now on the main / phone view, but would still like to know why.

Any hint / suggestion is appreciated.