Similar issue. My M1 2021 model stops working charging optimally with my 140w charger as soon as the battery drops below 80%. I believe that it has something to do with the optimal charging protocols; Lightning charge before 80%, and standard speed charge after 80%. In other words, if my battery remains above 80% charge, it's permanently fine. What's strange, is that my wife's 85w charger works fine at any battery percentage. So we've swapped. But I really pray that apple fix this bug soon.