Mining regular iron/gold ore with Silk Touch doesn't give the original block

[Naxdar]

Mining minecraft:iron_ore and minecraft:gold_ore with a silk touch pickaxe give the corresponding unearthed ore item (unplaceable) instead of the original block.
The other iron/gold ores (inside unearthed stones) do give back the original block.

Versions :
Unearthed 1.1.1
forge-1.16.5-36.0.42