Nether cave carvers cannot cut through deepslate

Deepslate doesn't exist in the Nether so this is to be expected.

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Deepslate doesn't exist in the Nether.

Deepslate is the universal uncustomizable underground below 0 block that always generates when enabled. So, it exists in the Nether, just not in the default Nether, you have to enable it.

I'd still argue that doesn't change the fact this is a feature request 🙂.