I just updated to the 2019 version of Adobe InDesign and was sent a file that was created with the same version. Some of the background was made using a gradient and disappears (becomes white) when I export to PDF. My colleague is able export and retain the gradient no problem, so it seems like it is a bug or setting that got changed. My InDesign expert colleagues tried basic troubleshooting and couldn't find the answer, so it doesn't seem to be obvious. Any ideas? Thanks!