It’s probably some critical bug in SpringBoard’s battery state where the icon’s reading stale / corrupted data from the BatteryUI framwork. The percentage text correctly accessed the real-time battery API, and the icon refreshes in larger intervals (5%-10% changes) so there’s slightly different render pipelines. I’m assuming this is iOS 26 beta which Apple’s already patched to correct a state battery state issue. Not an expert and I’m just guessing.