Seed, coord, specs included in screenshot.

Seed for easy copy/paste: 186769178758236173

Flying around in spectator mode, I noticed some ravines clearly cut off by lava lakes and mineshafts. Initially, I was looking at the generation rate of ravines (most times, I can count 6-8 ravines in any given viewable area ). I think it issue may be ravines also generate so frequently, they're running into other underground structures.