System navigation with swipe gestures

When I reboot my Fairphone 5 e/os, the swipe gesture from the bottom up does not work anymore and the screen is entirely black. However the notification panel works so I go from there in the settings.
Then when I try swiping from the bottom up, the screen freezes and I can’t scroll anymore.
So I go again in the notification panel and the settings. Then I switch the system navigation to 3 buttons and it works perfectly! And I switch again to gestures and it works.

So why doesn’t the bottom part of my phone work at first ?

Welcome to the Community forum.

While I have different device (FP3), I have had a slightly similar problem with gesture nagivation for several months now (it first happened before 2.9 and persists now under 3.0.4):