I found this bug as well while caving in a mountain biome. I can confirm that this happens in 1.17 pre-2 as well. Attached is a screenshot of an area excavated at 503 242 in a mountain biomed on the seed 5066170007265903118 in 1.17 pre-2. I believe that this can be replicated on any seed.
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It looks obvious to me that this ore spawn rate is much higher than intended.
Nathan C
Tested again, still happening in 1.17 pre-5
[media]I found this bug as well while caving in a mountain biome. I can confirm that this happens in 1.17 pre-2 as well. Attached is a screenshot of an area excavated at 503 242 in a mountain biomed on the seed 5066170007265903118 in 1.17 pre-2. I believe that this can be replicated on any seed.
[media]It looks obvious to me that this ore spawn rate is much higher than intended.