After using sprite:setScale the image will no longer be inverted. Not sure if this is a bug or just me using the wrong method.
Here is an example of the problem (please ignore the wrong usage of setCenter, it doesn't impact the outcome)
With setScale the original image is used
invertedImage used properly when setScale is commented out
It is very easy to reproduce, you just have to use sprite:setScale after using an image:invertedImage() in the sprite constructor.