The All Cure Potion from CWK.

I don't know if this has been discussed before but last night when I was buying some all cures from CWK at DMG (Dead Man's Gorge), I noticed those all cure pots were not stacking with my other all cure pots that I usually buy from Alcaster or pick up from random monsters. Also when I dropped all my all cures to reloot to see if they would stack, the ones I bought from CWK just disappeared and didn't show up in my inventory, but my other all cures were fine. Just wondering if this a known bug or something?