Hello,
I've bought my laptop about a year and a half ago it's a HP Spectre x360 Convertible 13-ap0xxx and I still have an active warranty.
So I've been recently getting this message:

And I've tested my battery using HP hardware diagnostics and HP support assistant and the results I get are that I passed and that my battery is ok.
In the last couple of days my laptop has been shutting down with a battery charge level of 20%!!
I would really like to solve this annoying issue as my laptop is still brand new, and I bought it for its amazing battery capacity!!!! I also would like to know if my warranty covers the change of battery in case it was deemed necessary to do so in order to solve my problem.