Seed and coordinates are in attachment for broken mansion.
Mansion (and possibly other structures)
generate(s) before water lakes are generated.
(not tested with other world features)
Related issues
Attachments
Comments

[media]

I think it relates more to MC-610 rather than duplicating it.
either that or the name of that ticket is not informative enough.
Since the mansion is a new structure, it's behaviour also might be different.

This happened to me with a lava lake, my mansion was missing an entire half! anyway this needs to be fixed, I don't want to walk 20k+ blocks to find a burnt down mansion!