Chosen Solution
I replaced my battery with the iFixit kit (MacBook Pro 15" Retina (Late 2016-2017) Battery) , and went through a couple of cycles of charge/discharge to reset the battery controller. I still get the message in the battery control panel “Your battery capacity is significantly reduced…” Following advice found elsewhere, I also did a shift-control-option-power up to clear the System Management Contnroller I still get the message. Everything seems to work fine, but I’d like to fix this so I know if there really is a problem
Shutdown and carefully disconnect the battery, now press and hold the power button with nothing connected for a 15 sec’s to fully drain the logic board. Reconnect the battery and power adapter let the system charge a good 5 hours. Restart your system and check the battery using CoconutBattery take a snapshot of the apps main window and post it here for us to see Adding images to an existing question
