Sunken Indonesian submarine underwent an overhaul and modernization period at a shipbuilder of South Korea in 2012.

「文大統領、インドネシア海軍潜水艦沈没でお見舞いメッセージ　韓国で改修した潜水艦が沈没し乗員全員が死亡」 https://t.co/7xydZXxW8S
この潜水艦、全電源喪失により沈没したが、2012年に韓国の大宇造船が行った大改修が問題との見方が強い。

— H.S. Kim (@xcvbnm67890) April 27, 2021

 KRI Nanggala was a Type 209 diesel-electric attack sub, one of many built by Howaldtswerke-Deutsche Werft (now ThyssenKrupp) in Kiel between the 1970s and the mid-2000s. The highly successful class was developed specifically for export, and more than 60 were built and sold to 13 nations, including two for Indonesia. KRI Nanggala was delivered in 1981, and she underwent an overhaul and modernization period at DSME in 2012.

DSME

From Wikipedia,

Daewoo Shipbuilding & Marine Engineering Co., Ltd (Korean: 대우조선해양; abbreviated DSME) is one of the "Big Three" shipbuilders of South Korea, along with Hyundai and Samsung.

2012年に改修していままで問題なかったわけだからなあああ・・・・