Add the Seoul Central District Prosecutors’ Office to the growing list of government units around the world that are investigating Apple over the reduced performance of iPhones with older batteries inside. The company’s poor messaging about an iOS update intended to prevent unexpected shutdowns — a change that required throttling the processor and slowing performance of iPhones with chemically-aged batteries — led to widespread controversy and customer frustration late last year.

As reported by Apple Insider, the new probe comes after Seol’s Citizens United for Consumer Sovereignty filed a complaint against Apple that claimed the company is really slowing down iPhones to sway consumers towards upgrading sooner than would otherwise be necessary. This accusation of deliberate deterioration is one that many people have turned to, though it doesn’t really hold up from a customer loyalty perspective. Apple has denied any kind of early-upgrade conspiracy, and last week CEO Tim Cook told ABC News “we deeply apologize for anyone who thinks we had some other kind of motivation.” The company also published an open letter on the matter on its website and reduced the battery replacement fee to $29. .

But in that same ABC News interview, Cook touched on the problem that led to this avalanche of bad press and angry customers. “When we put it out, we did say what it was, but I don’t think a lot of people were paying attention. Maybe we should have been clearer as well.” I’d say the number of investigations into the matter and amount of blowback Apple has taken are enough to eliminate any “maybe.” (Apple is also facing probes in Italy and France.) With the release of iOS 10.2.1 in 2016, Apple indeed touched on reduced shutdowns and deeper battery management — but any update that eventually slows down a very expensive smartphone deserved a more up front, obvious explanation.

Cook has said that an upcoming iOS update will offer more detailed battery health information and allow customers to disable the performance throttling. Doing so would leave the user experience unaffected but might increase the risk of annoying shutdowns when the battery still has a charge.