ArcGIS Hub Bug Broken PDFs

[Ed_]

Hello, 

I embedded a Portfolio Instant App which has a multiple PDFs in it into a Hub page, but the PDFs are broken. The PDFs can be viewed fine when the Instant app is opened on its own.

How can I fix this? 

As seen in the Hub page on Chrome

As seen in the standalone app on Chrome

It's not working on Edge as well.