I had the ‘error 500’ and I noticed that ‘auto save’ was not working.
I went back to my dashboard and reselected the post I was working on. I made my changes and selected ‘preview’ and was taken to a blank page.
I reselected my admin Dashboard and reselected my post. None of the changes were saved. Made my changes again, and clicked ‘save draft’, was brought to a blank page.
I reselected my admin Dashboard. This time there were two of the same posts. I selected the top one and that had my changes, the other had no changes saved.
I reslected the top post and clicked on ‘preview’ and was able to see my post with all my changes but the permalink structure I had just changed was not being displayed.
I went back to my dashboard and edit post to select ‘publish’, and was brought to a blank screen.
I reselected admin Dashboard and there was the saved post as a draft and not published.
Decided to come here and see what I was doing wrong but it looks like there are a lot of people with a wide variety of problems with upgrades and the functionality of 2.8. Hopefully there is a fix coming along 2.8.1 for everyone! Until then, lots of drafts will be waiting.
Permalinks: changes were saved on my admin dashboard. Old permalink structure still in place on posts.