Aetherial Reduction is still possible at Crystal cap 9999

Can still use Astherial Reduction with no warning imposed when you're at the crystal inventory cap of 9999

For instance, reducing a Clary Sage at 9999 Wind Crystals will still net you an amount of Crystals, however they are not added to your inventory and end up discarded without notice.

Don't think it's a bug, just inconvenient.
I mean when you're fighting mobs for drops you don't get a warning when your inventory is full and the mob drops something, do you? It just disappears.