We're having a hard time knowing if the Alt key is pressed on windows 8 when PT has the focus (using getCurrentModifiersRealtime and IsAltDown).
We tried by directly calling getAsyncKeyState and reproduced this bug, so I don't think it's really Juce related, but I thought it could be interesting to see if someone else have the problem (or just to let you know).
Other key are working correctly (meaning, we know when they are pressed), and it's also working correctly when PT don't have the focus.
[EDIT]: for information, we found that the AAX wrapper offers way to get modifiers from the host. With those calls the modifiers are correct.