Overheating batteries cause problems for Apple

Affected units were sold primarily between September 2015 and February 2017; specifically, this issue affects some Mid 2015 MacBook Pro 15″ Retina models. Repair shop iFixit suggests that a faulty battery might be the cause (rather than a design flaw): "We can’t say exactly what’s causing the issue, but considering the 2015 MacBook Pro’s design was mostly unchanged from the prior model year, all signs point to defective batteries rather than a larger thermal design problem. So as long as you get your battery replaced, you should be golden".