HIP 40906 is a Class A III giant star. Given the description for water giants in the system info, I'm going to guess they're more likely in systems with a non-main sequence giant, as the increase in size and luminosity of the star as it evolves cause more energy to arrive at outer massive icy planets which flips them into a water giants.
Whether I'm just blathering on nonsensically or whether the proc gen is really REALLY clever and actually doing that, I'll leave up to you![]()
Sounds plausible.
(I think the ordinary gas giant model draws from both incident radiation from the star and the giant's own mass to calculate its temperature; the closer to the star / brighter the star / higher the mass of the giant, the higher its surface temperature works out. Once it has the temperature it picks the appropriate Sudarsky class. And that'd be why we don't always see the classes in a nice line from V closest to the star to I furthest away.)