This only works if you had the Alchemist Flask's buff on you before the servers went down (a very likely scenario considering the buff duration and that is persists through death). The buff you have on you is the old buff that gives 320 to your main stat instead of the new 20. And if you drink from your flask you refresh the old buff instead of applying the intended 20 stats buff.
This is not a display bug, I canceled the buff on my mage and lost 320 intellect.