Quick Look Index View and PDF hidden content

I have come across an odd quirk of Quick Look in which the Index View is different from the regular view. The Quick Look Index View of two or more PDF files will show hidden page or image content, while the regular view of the individual files will not.

The hidden content consists of one portion of the text covered up.
Preview does not show the hidden content of an individual file, but QuickTime does.

Is this inconsistency of Quick Look a bug?