Subsequent patches should typically be found under"water"; they may be a substantial distance from your initial landing site, and have to be mined with seafloor drills. It's possible something is interfering with their spawn conditions; I've just validated that they are still spawning in the latest experimental build.
As a quick test to see if you're not just unlucky with proximity and something actually broke, you should be able to see at least one such patch if you look at Aquilo in map generation preview; if not, provide me with your mod list and I'll see what I can do.