This is a problem that I have also had and that other users complain about. It usually happens in situations where the Netgear device is on the charger 24/7. I think the Netgear engineers thought that the constant charging would damage the device.
I have already observed this: After about 2 days, the device began to automatically discharge by about 1/3.

You usually have to wait a few hours (+ disconnect the charger), then the device usually charges to 100% again. (The whole thing repeats itself after 2 days).

Since then, I no longer use the unit in continuous operation, but disconnect it from the mains and switch it off when I don't need it.

P.S.: At least the battery would be easy to replace...

Hello

Have you been able to test with another power supply unit whether this also occurs there? To rule out a loose contact. Is a firmware update possibly due?

If none of this helps, I would recommend an exchange.

Greetings