Benchcraft on Helical Ring not possible?!

I have a rare Helical Ring with fractured all ele res as the only modifier.
There should be 1 open prefix und 3 open suffix, but when i try to benchcraft any mod they are red with the tooltip "Item has no space for more Crafted Mods" and the Craft-Button ist grey.
I tried a few things like crafting with essences/annul/scour und having another player try to craft, but nothing works and at this point i don't know what to try anymore...

Does anyone have an idea why it doesn't work?

Also the ring is split and has 20% res quality if that matters.

"

seaman#4993 wrote:

This all ele res is probably a crafting mod.

This was it...
Thank you for the help!