I doubt this was intended, but with a combo of mods, you can duplicate diamonds. You can use the crusher demons from Occultism (higher tier ones) to crush diamonds into dust resulting in 2+ dust piles per diamond. Then you put the dust into the enrichment chamber from Mekanism to turn it into a diamond. Rinse and repeat for more.

Again, I don't know if this is an actual issue or not. Definitely not a big one at least. Just thought I'd mention it

Should be fixed in 0.5.9 :)

This should be fixed already. Can you please update?