I was told by someone on the boat at the time that it came out of nowhere and blindsided everyone. They were recalled and the only criticism they leveled was it took too long for all the divers to get out of the water. Which... not sure if that falls on the boat or divers or what.
I have never been on that trip nor am I the expert for swells or weather nor do I run dive operations, but that is what the reputable observer told me.
Squalls can come up quickly, no doubt. The boat crew must have been hustling, trying to get everyone back. Tough day for all involved.