Shouldn't this return true? I guess it's a bug
The code above is more of a test than anything else.. Meaning that either ImageInstance doesn't recognize the image correctly or the Wolfram knowledge base doesn't give the right image in this particular case. I guess it's the second one, given that ImageIdentify classifies that image as European wildcat as you say.
A similar test:
The image is identified as a 'European wildcat' rather than a 'domestic cat'.
ImageIdentify@image
ImageInstanceQ[image, "cat"] (* True *) ImageInstanceQ[image, "wildcat"] (* True *)