Having similar case with my old mbp 2016 battery kaput some otwo-weeks ago. Replace it with “SIMPLO” OEM battery.
Within less than a month, the health reduced to 96% with only 7 cycles.
Upon replaced, I tested unplugged until it drains to 90%. Charge it to 100%. Let it plugged for a night. The next day I drained off and recharge it to 100%. Then my normal usage, which is.. usually plugged in during work on desk about 6-7 hours. Some mobility with battery left to 90%-80%.
Also is this normal?