service battery

Coincidence, most likely. Regardless if your Mac reports service battery, the battery needs to be replaced soon. It will still run, but your run time on battery will be reduced and it may shut off suddenly even though it reports well above empty.

Replacement cost ranges from $129-$199.

https://support.apple.com/mac/repair/service

With Catalina and Mojave, an SMC reset was sometimes needed after updating to get the battery systems to report properly.

Please be sure to identify your MBP model before doing the reset, and pay attention to the parts in this article regarding the T2 Security chip:

How to reset the SMC of your Mac - Apple Support

Coincidence. How old is your Mac? Don't ignore it for long, swollen batteries can ruin the rest of your Mac.