MacBook Pro battery setting that limits charge to 80% not working

Hello TidBits experts:

I have a related battery/settings issue, not related directly to the iPhone, but rather addresses a battery issue I am having on my MBP (2019, intel chip, running macOS Sonoma 14.7):

The issue: I do have a constant power supply to the MBP. I also have the battery setting to kick in with the 80% charging level, eventually, when having a power supply connected.

The 80% did work once, then I disconnected the power-supply for a while, then reconnected the power supply, and the 80% charging level never returned. It remains at 100% charging, and I still have the 80% option chosen in the battery settings.

Am I doing something wrong, or is there a known bug with my configuration, or what ?? Please advise. Note: I do have a “Service Recommended” notice attached to my MBP battery (which I am currently ignoring), so I am not sure whether or not this situation will be contributing to my MBP battery charging issue.