Document has items and pages that randomly disappear. I get them back most of the time by clicking on another page then going back to the page that disappeared. I have 12gb internal memory so rendering isn't an issue I don't think? I even took the time to rebuild the document on another .indd file. I'm using version CC and per creative cloud it is the latest update. I can't work like this when I have print deadlines!
I solved my own problem!
The issue is text threads. I went to view > extras > show text threads and noticed that my text box on page 3 was threading to a text box on page 15 which is why it showed the pages in between as blank. I re-threaded all the boxes properly and everything is great! A good explanation and tutorial can be found here.
I hope this helps someone else!