Tiny Bubbles in the wine (I mean part)

[joeprocess]

Have this very unusual issue with a specific Lexan material. It shows itself in a few different parts that we mold for this project. It shows in the thicker sections of the part. It does not happen if using other PC materials. The material is tested as dry. I believe the bubbles are small voids, but the melt stream has these bubbles as well.

What I'm scratching my head about is that when the part is filled to 100% on 1st stage without pack/hold psi/time there are no bubbles. When the part is packed out the bubbles show up. The fill only part does not show any voids or sinks anywhere on the part either. See attachment.