Twisp & Catsby clarification

[Clipper]

For consistency with the rulings on Big Joe, which is a card that can be either a Hireling or a Steed, I think the attachments remain attached, even if the Item failed to be what it was before, but they no longer provide a bonus when they are attached to the wrong thing.

So you don't discard Air-Cooled, it just stops providing any additional bonus.