Warm/Lukewarm/Frozen oceans are extremely rare

I've tried creating multiple new worlds each with different seeds. Every time I've failed to find any of the other variants of oceans other that "Ocean" and "Deep Ocean" biomes. It seems to affect every world created in the snapshot.

Note that in prior versions warmer variants of oceans weren't as hard to find as they are as of 18w15a. I don't know if this issue is only affecting me for some reason or if it persists with others.

Edit: I've added two photos that show what all the ocean biomes look like, as seen, there is no variation at all. No warm or frozen variants can be seen throughout the world. (Sand doesn't generate on the seabed, nor do reefs or icebergs).