Apple Pencil

Translation:

It can be charged with a case, but the charging stops occasionally. It was charging when it was first put on, but after a while, it stopped charging without moving the pen. It happens several times a day, but not always. Is it a hardware problem, or is it because of iPados16?

If you are running a beta version of iPadOS, as now indicated, you should have full expectation of encountering issues and bugs. The Terms of Use that govern participation within these support communities disallows discussion of beta release software and associated issues.

If you are currently enrolled in a beta programme and wish to return to using the current production version, this support page provides the necessary information to remove the beta from your iPad:

How to uninstall iOS beta software - Apple Support

iPadOS 15.6 is the most current production release.

Translation:

The pen will start charging when it is put on, but when the lock screen waits for a while, you will find that it stops charging, but there is no place to move the pen. After repositioning, the charging continues. The figure below is what you saw when you open the screen.

Your iPad appears to be in a fitted case. It is highly likely that the case is displacing the Pencil from its correct location for charging.

The Pencil must be precisely located - and have physical contact with the edge of the iPad - to reliably charge. Remove the case from the iPad and test.