[jahewson]

> which suggests that Edge's PDF engine is re-rendering the original PDF, rather than printing the original PDF as is

That's to be expected. The bitmap which Edge has rendered to the screen is not what will be sent to the printer driver. Instead, rich vector graphics will be sent. On Windows, the native print format is XPS, so this is most likely a bug in how Edge converts PDF to XPS for printing.

For simpler use cases Windows' graphics APIs can be used to both render to bitmap and to XPS but when printing something as rich and sophisticated as PDF better results are achieved by directly targeting the native print format, such as PCL, PostScript, or XPS. I suspect that's what the Edge devs have done and why it's producing different results on screen and in print.