Fanatic's Tonic effect altered?

While farming for feet in Attohwa Chasm [A] among the mandies there, a blue chest containing a Fanatic's Tonic dropped. I used the one I had, and picked up the new one and went back to farming, only to find the mandies were still hitting me for damage. It was one half or one third normal damage. I went to effects and found that I had Defense Bonus rather than Physical Shield(I can't recall if it normally reads Defense Bonus, I seem to recall Physical Shield but that could be my faulty memory. Later I used a Fanatic's Powder, and that worked fine, zero physical damage taken.

No other Fanatic's Tonics dropped, so I don't know if it was a one time thing or what. I'm wondering if anyone else has had a similar experience. If anyone can check to see if their Fanatic's Tonics are working properly, it would help determine what's going on, if anything. I'm going back in(damn elusive rdm feet), and if I get the chance I'll check it again.

Fanatic's Tonic has always reduced Physical damage by ~50%

the "100%" PDT you're thinking of is Fanatic's drink.

Its two different items :X, Their in-game Description is lazily screwed up though.

Ah, is that the case? Then yeah, that's messed up. I thought the difference was in duration. That may explain a few times went I went for a Fanatic's as a last ditch save and still died. I always thought I just got hit before the drink took effect.

Huh.