Macbook battery bar showing as red; battery % jumps around; battery condition normal; out of US charging
I would start by resetting the System Management Controller (SMC) which is responsible for power management and controlling the thermal environment of your Mac. Typically this covers things like interpreting and responding to various sensors, battery charging, sleep/wake/hibernation, the power button and restarts/shutdowns, LED indicators, and so on.

To reset the SMC on your model MBP follow these steps:


Fully shut down your MBP
Press ShiftControlOption on the left side of the built-in keyboard, and press the power button at the same time
Keep holding these down for at least 10 seconds before letting go
Power up the MBP again


Once you've done this keep an eye on your battery status to see if you notice any changes.

As an aside, I note your battery has a cycle count of 837. To put this into perspective, your MacBook Pro battery has a life expectancy at or around 1000 cycles.  It's not uncommon for batteries to exceed or fall short of this number; it's just an estimation of how long it can last.   You can refer to Determine battery cycle count for Mac notebooks on Apple's website for more info.

As your battery condition is listed as Normal I wouldn't be too concerned about the cycle count yet, but you may need to think about a battery replacement in the not-too-distant future.

You may also like to take a look at How to reset the System Management Controller (SMC) on your Mac. It provides more info on what the SMC does, when you to reset it, etc.