On July 30, 2020, During an at-sea pre-deployment training exercise of the 15th Marines Expeditionary Unit, eight infantry Marines and one Navy corpsman drowned as the 26-ton amphibious assault vehicle transporting them to amphibious transport dock ship USS Somerset sank.
In the ensuing Marine Corps investigation, Col. Christopher J. Bronzi, commander of the 15th Marine Expeditionary Unit, was relieved of duty in March 2021 due to a "loss of faith and confidence in his ability to command," a Marine Corps statement said.
The investigation also faulted Castellvi, commander of the 1st Marine Division, and noted that the platoon aboard the AAV had not completed its mandatory Marine Corps Combat Readiness Evaluation, or MCCRE, prior to the accident.