Duplication of content

OK, so I'm producing a magazine that's an app in the App Store. And for those who prefer to read the magazine on a desk / laptop. I publish a copy as a flipbook in PDF format on a free Issuu account.

Every month I want to copy the mag articles of the previous month into my WordPress blog as they are a good cornerstone. But if Google already indexed the PDF flipbook on Issuu, they'll think I'm just copying another person. satisfied and punish me?

cheers