Battery percentage is not normal

First of all, which Mac model do you have?

This issue may be caused by the battery reaching the end of its lifespan. All post-2009 MacBook Pro batteries are designed to last about 1000 cycles before needing to be replaced, by the end of which they can usually retain 80% of their original capacity. Maybe it's time to replace your battery.

Here's how to check your battery health:

1. From the Menu Bar, choose 
2. Hold the "option" key and click "System information"
3. Select "System Report"
4. Under the "Hardware" section, choose "Power"
5. Check the "Cycle Count", "Condition" and "Maximum Capacity". Post-2009 Mac Pro batteries have a "life" of one thousand (1000) charge cycles. If you have exceeded 1000 cycles, maybe consider replacing your battery. If your battery "Condition" is something along the lines of "Service Battery" or "Needs replacement", then this is what may be causing your issue. (see attached screenshot from my laptop)

For more information on battery health, power cycles and getting help:

Get help with your Mac notebook battery - Apple Support

Determine battery cycle count for Mac notebooks - Apple Support

Batteries - Why Lithium-ion? - Apple

-flef

ivan_lju wrote:

After last system update 12.4, my battery percentage is jumping... 13%, 30%, 22%, 11%, 17%... macbook pro is not plugged in

M1— try SafeBoot How to use safe mode on your Mac - Apple Support to sort anomalies.

Intel—Try resetting the SMC How to reset the SMC of your Mac - Apple Support

If you Option-click the battery icon on the menubar does it show the battery condition? If the condition is "Normal" macOS no longer displays the condition, but if the battery is below 80% of its Design Capacity or failing, then the condition will be displayed as "Service Recommended".

You can also try running the Apple Diagnostics to see if any hardware issues are detected. Unfortunately the diagnostics don't detect most battery failures. In fact I now look for odd behavior such as you are describing where the battery values fluctuate back & forth instead of steadily increasing or decreasing. We are not currently running Monterey so I cannot confirm, but it will be interesting to see if the same patch is applied to Big Sur and Catalina. Unless others report a similar issue, then maybe it is just an unfortunate coincidence that your battery just started to show this behavior at the same time as the update. FYI, if the diagnostics report a battery failure, then that is most likely independent of the OS update.

I'm not quite sure, as the update is still quite new and I wasn't able to find anybody with a similar problem to yours.

Furthermore, try recalibrating your battery to see if the problem persists. Here's how: https://www.newertech.com/batteries/power-calibration-guide/

What I recommend is submitting a bug report on Feedback Assistant - Apple Developer

On my MacBook Air (A2337) I haven't been facing any issues. Have you also noticed that your battery is draining faster than normal, apart from the inconsistency in displaying the charge left?