Cask seems to 'forget' installed software?

[SuperHenkie]

I installed several apps through brew and brew cask. Occasionally, I noticed that when I do brew cask info programxyz it says "Not installed", even though I most certainly did install that particular program through brew cask earlier.

For example, I have installed Firefox a while ago using brew cask install firefox.
Now if I do brew cask info firefox it says "Not installed". Note that the alias and the .app are still there, and Firefox works fine (I'm typing this in the cask-installed Firefox as we speak, actually).

I frequently do brew update, brew upgrade, brew cask update, brew cleanup etc.

Is this an issue in brew or cask, or in the particular app, or am I mistaken or doing someting wrong?

[vitorgalvao]

#2988.