"block_experience" enchantment effect doesn't affect XP dropped

In the attached enchantment json, I have "mob_experience" and "block_experience" being increased, even at high values the blocks still drop the same amount of XP.

 

When I copy the vanilla silk-touch enchantment, this also doesn't affect it.

 

Therefore, Silk Touch must also not work correctly and uses some other method of configuring the XP drop