Today I've been troubleling with the publishing prototype option. Everyday after I finish my work, I publish everything done for sharing it. Today, when I was checking it out, some elements from the design disappeared. I openned the document once again thinking I just maybe deleted them unintentionally but, they were there and they also appear using the preview option. I already tried creating a new link and pasting again these elements but nothing worked.
Had the same problem today, prototype working perfect then the chevrons disappearing on export. I remade them as a path in the file instead of a text element and when I shared them as a link they appeared as normal, not sure if this will be any help for you but thought I would post it just incase, very frustrating.
I had the same issue, but thought I would pass on the mistake I made. My component was a copy amd paste from another page and it kept dissapearing from the new paste position.... it was checked as 'Fix Position When Scrolling' on the first page and this attribute was copied as well. Just unchecked that on the 2nd instance ... perfect. Live and learne!!