I just checked this. The good news is, what is actually happening is correct. However, there are some mistakes in the interface:
1) Caravan Guards prompt to play it in response to an attack says "reveal" instead of play.
2) Playing Caravan Guard in response to an attack leads to the wrong number of actions being displayed (but won't actually add to the action count of the active player) (this is already known)
To block Young Witch's curse with CG, you need to first click "Don't react" in response to YW being played, then reveal it in response to the curse gain after the player playing YW draws and discards his 2 cards.
1) Caravan Guards prompt to play it in response to an attack says "reveal" instead of play.
2) Playing Caravan Guard in response to an attack leads to the wrong number of actions being displayed (but won't actually add to the action count of the active player) (this is already known)
To block Young Witch's curse with CG, you need to first click "Don't react" in response to YW being played, then reveal it in response to the curse gain after the player playing YW draws and discards his 2 cards.