It is a problem with their loot_table.
For some reason, he is using one, even though he changed nothing in it. The problem is that the new loot_table has different names. Which means his loot is not replacing the ones from the game.
The game has now very high values for the chances of each ore, his loot_table is based on the old values.
From all the possible loot, the only one his loot_table is able to replace is the stone (which kept the same name). So the stone has the old low values, and the ores has the new high values.
Anything mined will be almost always ores.
To fix this, I recommend erasing completely the custom loot_table, as it is not necessary for this biome (was applying no changes)
At anorien_biome/data/biome/anorien.json erase the line with: