Reported by: @JfromHolland29

I think stuff like that "Objects spawned in a new chunk, but extend to already replaced chunks don't have their blocks replaced in the existing chunk." happens with lava lakes in snow biomes. Often half of them is lava, and half of them is a mix of ice, water, lava, and obsidian...

In Vanilla, Lava lakes don't have a freeze effect. 8b6e59d fixes this and adds the ability to make ALL lakes fully frozen, as well as turn on lava lake freezing. See this post on the forum for more information.