These potions from Zatauro's Ascent do not add withering to the counter, and was thus told to post a bug report by the automated message.
Blighted Potions of Bull's Strength from Zatauro's do the same.
Mine did this too but mine were from Thomas
Additionally, I have experienced on two occasions that if a Mimic Sorcerer attempts to use a withered potion to cast a spell, they are unable, but the potion no longer adds withering. Although I am unsure if the potions would have added withering before the player tool was used. I'll test it out next time i have withered potions and meet a mimic.