What is the deal with Apple iPhone 12mini battery issues

This is second time I’ve personally had to bring in my iPhone to APPLE for a 12mini for a ‘battery health issue’. My phone has been down for almost a week as I’ve bounced from T-Mobile to T-Mobile store & then to Best Buy where a agent/technician at every stop has validated it’s a systemic reoccurring problem they’ve seen with specifically the 12mini. WHAT is going on?