Hmmmm... That's weird. There are indeed Volcanic Ocean tiles, but they should only be fonund on the shoreline of volcanic regions or as the result of a Volcanoformation Device going off. Would you happen to have the Save Game for that game, so we can take a look at it? Thanks!

Yes, the world generator is not asking if a region is oceanic or not when choosing its biome, some oceanic regions end up being volcanic, at first this wasn't a real concern, but with the addition of health regen inhibition we should have prevented this, I'll see to get this one fixed