I’m using Adobe Illustrator and I’m having an issue with a stroke, which has a custom gradient brush applied. It’s not showing up in the PDF file after I export. It shows up just fine in web applications, but when I render it as a PDF, it doesn’t appear in the artwork upon opening.
had the same problem: turns out my color formatting was set to RGB, not CMYK. I haven't the slightest clue why that makes a difference when exporting gradients in a PDF, but switching the color Profile to CMYK fixed it for me.