Owners of Jumbo Floating Restaurant backtrack on sinking claims as authorities investigate
https://edition.cnn.com/2022/06/24/asia/hong-kong-jumbo-restaurant-sink-investigation-question-intl-hnk/index.html
I think the floating restaurant won't be able to keep floating when encountering high tide or storm. So, it's dubious that the statement "quite uncommon" for a vessel to sink simply due to bad weather".
And also, it's also dubious that the investigation is difficult. As I introduced yesterday, there is a team investigating wreckships located at more than 6000 meters deep under sea level.