ESP32 available in HA but not by IP

I have a strange issue with multiple ESP32 boards that are available in HA but not visible in my network, cannot be pinged, etc…
I am now focusing on an ESP32 flashed with WLED and I set a static IP to the board in the WLED software.
This one is available in HA but nowhere else.
If I check devices connected to my router, it’s not there.
If I try to access the board by it’s IP, no success.
If I ping the IP, no answer.

This is sort of mistery to me, any idea ?