Nothing specific to that potential use I can cite, given we were talking about what was possible, not necessarily what happened given the lack of hard evidence in any specific direction; there have been reports of jamming under other circumstances aboard or near cruise ships or their ports. There have been reports of widespread use, whatever their legality, in theaters overseas after the idea being shot down in the US despite requests from the industry to allow it. And they are widely available. I would post a link, but don’t want to help their business. If curious, Google “jammer store” and if you want to jam it, they probably have it.
From a gov’t briefing on the issue in the US, with several instances of maritime use that certainly raises the possibility of jammer use, not necessarily by the ship itself: https://www.gps.gov/multimedia/presentations/2017/02/COPUOS/hamilton.txt
As that report noted, jammers tend to be dirty and indiscriminate, reason they are also illegal, so they don’t need to be oriented toward a specific band or service to cause problems for services like the goTenna supplies.
Another possibility is jammer use against drones: https://forum.dji.com/thread-35974-1-1.html
Speculative, too, but the comments about radar in that thread raise another possibility for the source. Lots of things like that on a ship. But they also run wifi and given the number of complaints about overcharging for such services, seem to wanna run their own game in providing cell connectivity at a price that they wouldn’t want to interfere with.
Yes, illegal many places, but also used where illegal for many reasons, including documented incidents of use by individuals who simply think people spend too much time yakking on their phones. But it could be any one among a lot of things, as my 3 decades of radio monitoring experience suggests to me. The one place where such use would be reliably legal actually would be in international waters, which could account for the lack of formal complaints there along with no relevant reporting or enforcement agency unlike in domestic waters.