Miscellaneous: Rune of Catalyst

[driz]

Beginning to believe that the rune of catalyst drop rate is bugged.

I have checked oasis, SolA, OOT, NK, EK, HHK CC, rathe mtns merchants for the runes. I have found 15/16 lvl 34 spell runes, only 1 i havent seen is Catalyst.

I have solicited 10+ people farming giants, cyclops, spectres, and griffons in the above zones to tell me when the rune drops to send a tell. No one has seen it in awhile.

I have been farming HHK goblins and Mistmoore CE for awhile and havent seen it.

I checked auction tracking and i haven;t seen the spell circle of force for sale in many months even though many are looking to buy.

Is this just an ultra rare rune, am i killing the wrong mobs or is it bugged?