Naps are not detected with Fenyx 8 51mm

Hello,
I have the fenyx 8 51 amoled and my naps are not detected.
I have the latest software and my watch is correctly positioned on my wrist.
Sleep is detected but not naps.
I have to send it back to Garmin France for testing.
It's a disgrace at 1,200 euros a watch.
Do you have any ideas?

Thank you in advance for your replies