Not that unusual. Just a month earlier, 25 passengers were injured on a flight coming into Hawaii from Phoenix, 6 of them severely enough to require hospitalization. [0]

"Between 2009 and 2021, at least 146 people, including passengers and crew members, were seriously injured by turbulence ..."

[0] https://www.nytimes.com/2023/01/14/business/hawaii-airlines-...