Battery status changing when connected to power supply

[NKP27]

My Spectre notebook was recently in for service when it shutdown mid-way through a Zoom call and I couldn't reboot it. The stated problem was 'incomplete BIOS'. Since it was returned to me, I have noticed that the battery charge level randomly drops to around 80% (sometimes 81%, sometimes 82%) even though it is connected to power all the time. This happens between 2 to 3 times per day (currently). 

After disconnecting it from the power source and then reconnecting it, the charging light is orange for periods ranging between 4 to 30 seconds after which it changes to white and the battery charge resets to fully charged (100%). 

During one event, I ran the 'Device Health' on the HP Support Assistant, and it said the battery need to be replaced as it wasn't charging. When the charge is 100%, the battery status is 'Normal'.

Does anyone have any idea on what the problem is?

[pbroussard]

Sounds like the battery needs to be calibrated. Follow the steps here https://support.hp.com/us-en/document/ish_2268927-1713329-16  the third section called "Test the battery before Windows starts"

Take a pic of the results and post it here.

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[NKP27]

Thanks for your prompt response. I ran the test (#3 as suggested) and the battery 'passed' with no indication of any need to calibrate the battery (fyi - the stated charge capacity is 88%). Note - I did not manually calibrate the battery. After exiting the diagnostic, the laptop completed booting up as per normal and the battery status showing as 100% (I hadn't reconnected the AC adaptor).

After only a minute or so, the battery charge dropped to 93% so I reconnected the adaptor and it appears to be working correctly (in that the charging light is orange and the available charge is slowly increasing. 

I checked the log of available charge over the past 24 hours and, again, it showed the available charge steadily declining overnight (even though it was connected to power all night) to reach 82% when I booted it up this morning.