Just noticed that a couple docs created in 1.7.3 that are designed to be both printed (cmyk) as well as used for web download/viewing as rgb cannot be exported for pdf in 1.8 (not sure which beta this started in). The doc (4-pages) is a cmyk. But in 1.7.3 we exported a Web 192dpi rgb version using the More/Convert Image Color Space. In 1.7.3, the resulting pdf is rgb and no problems with it. In b549 using the same doc (opened in b549) and same export settings, several pics, graphics, etc are not being exported at all or correctly. Problems all over the doc. You should already have this doc (Clean Water 2019 - FW - 4pg.afpub) but can upload if you need it. I'm guessing that it is having problems converting some of the items. Worked fine in 1.7.3, so looks like a regression of some sort.
"More" pane settings attached. Started with PDF/Web/192 dpi + the More settings.