Have you tried to open the pdf in a text editor like notepad++ to see what it looks like? It might be that the stream is incomplete, or you're writing the base64 to the file output without decoding?

Although I have seen environments where namespaces are used to separate Dev/Test/Prod etc. I have found that having the Prod environment on the same environment as the Non-Prod Namespaces is a risk to the Prod environment should an active piece of development take down the underlying machine (one example was a developer* making a mistake when working with Streams and had created an infinite loop in writing a stream and the server very quickly gained a 10GB pdf that filled the disk to capacity and the environment stopped working).

A common use case for multiple namespace for me would be for instances where the activity within the namespace is significantly distinct from the others. For example, we have a namespace that is dedicated to DICOM activity. While we could have put this in a single "LIVE" themed namespace, the volume of activity we'd see for DICOM would have filled our servers disk if kept to the same retention period as other standard retention period. So we have a DICOM namespace that has a retention period of around 14 days compared to others that are between 30 and 120 days.

*It was me. I was that developer.