I have a 2019 MacBook Pro 15 inch running MacOS Catalina (10.15.6) which had the top case (battery) replaced in July 2020 due to significant battery degredation over the 1 year I had owned it. The battery health went from 100 % to 84% in just over 12 months.
Since having that replaced, I noticed that the battery health of the new battery had decreased from 100% to 89% over just 53 charge cycles. I called apple support since it still has apple care and they ran their diagnostics on it (Shut Down Mac, power on, hold option + D). The agent said the diagnostic report showed my battery was at 97% health which was within spec. I am just curious why system report would be saying my max charge capacity was at 6502/7336 (89%) yet his diagnostic (which apparently bypasses any operating system measurements) is saying 97%?
I thought this might be an SMC issue and reset that earlier this week but no improvements. Is there some other system that needs calibrating?