I don’t know from which release the issue began.
I realized that after I performed the following services in HA:
deCONZ: Device refresh
deCONZ: Remove orphaned entries
My 3 extenders aren’t listed in devices and entities.
It’s not a real problem because they don’t do anything in HA.
I just report that because Robban writes in this forum; Maybe it could be useful for him.