Optimized battery charging doesn't appear to be optimizing anything

Question:  Would appreciate if someone could explain under what circumstances “optimized battery charging” decides to hold the battery at 80% when on the charger, and when it decides to hold at 100%.  What are the basic rules "optimized battery charging" considers when it “learns from your daily charging routine"? The “optimized battery charging box” in preferences has been consistently checked/never unchecked.  The computer has a M1Pro chip, and always has had the latest Monterrey version.

Background:  During the first few months I had this computer, it seems like the charging would work as it should: frequently hold the battery at 80% (with the charger light showing orange) if I was working with the charger for an extended period.  More recently, it seems to always go straight to 100% and stays there, even if I am working on the computer for several consecutive days with the charger.  

This behavior causes me to wonder if this feature is currently functioning correctly on my computer.  I twice called Apple Support to ask what the general operating rules are supposed to be for this feature, so that I can determine whether it is working correctly.  They, including second level, have told me they don’t know how it should work, and therefore cannot tell me if it is or is not working properly, which is absurd. They said that Apple hasn’t shared this information with them.

I noted in these support pages that some users indicated a similar problem following the 12.3.1 update in April or so. I don’t recall if my problem started then, or perhaps a little before or after this. Apple also sent me a replacement battery charging cable this past June. I don't recall the battery optimizing holding at 80% since receiving this new cable, but also don't recall for sure whether this problem started before the cable change.

Help requested, please!