Original Apple battery showing up as unknown

Hi,

I have an iPhone 13 Mini which I have had for over a year. It has never had a component replaced and is all Apple Original parts. Today it has given me an ‘important battery message’ as it is an unknown part as if a third party battery has been installed. It has since stopped showing me the charging indicator and battery health. You can clearly see the battery level in the graph below battery health drop suddenly from around 30% to 0 as it stops being read by the OS. No parts were changed in this time period nor in the lifespan of this device.

Any help would be appreciated.

Josh