I am pretty sure no one on here knows what happened onboard the Connecticut. Someday in the future we may, but after a Navy inquiry and it’s declassified. These new boats can travel fast and do not turn or stop on a dime.
The simplest answer might be the right one. Charts have never been close to 100% in the open sea. They are better now than ever, but still subject to missed underwater obstacles especially in the pacific rim area. Underwater volcano’s and upheavals are quite common.The sea floor there is active and subject to change.
The SCS is a busy place, lots of entity’s jockeying for position. I was in the Navy aboard submarines as a Quartermaster in the years ‘64-68. Spent almost 12 months in and around the South China Sea on a diesel boat. Then later, three patrols on a boomer in the North Atlantic.
It is fun to think about it like a Tom Clancy novel and maybe it will be a chapter in one someday. For the brave men that go to sea in submarines, no matter what happened, it was their worst nightmare. I hope all are well and the boat can be repaired and return to sea to protect us all.