Did you happen recently that when your MacBook is connected to the charger, a warning is displayed saying that the battery is not charging? The "fault" is probably the update to macOS 10.15.5 Catalina and later, but it is neither a bug nor a device problem: in fact, it's quite the opposite – a software feature that promises to stretch the longevity of the battery.
The function is simply called Battery health management, and is able to stop charging it when it is superfluous. For example, the software monitors battery operating temperatures and usage history. In other words: it is useless to continue to supply it with energy after it has reached 100% and continue to use the laptop connected to the charger: it is subjected to a series of continuous "micro-cycles" of charge which do nothing but accelerate the chemical aging process of the components that make it up.
macOS 10.15.5 has been around for several weeks (in fact Apple has already distributed the next version, 10.15.6), but the technical support page that explains the meaning of the non-recharge indicator was published only in the 'last period. The functionality is available on all systems with Thunderbolt 3 ports – and of course the right version of macOS. In the support document, Apple specifies that there may be another reason for this warning to appear: the charger does not have enough power to recharge the battery.