I found that the generation of Igloos and Mansions seem to be broken. Grass, dirt, and stone are generating inside of Mansions.
Seed: -7090047633471018246
/execute in minecraft:overworld run tp @s -26880.96 79.97 4299.26 -316.05 -24.45
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The igloo part is MC-91084.
Can confirm in 1.17.1.

Duplicate of MC-107594.
Can confirm. This is a big issue in my opinion.
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