I like to open posts in a new tab and that seems to be the primary culprit.
Most of the time, when I do that and get an internal server error I can simply go to the url bar, click at the end of the url, and hit enter to get a page to load.
Sometimes I just need to click the link and not open it in a new tab.
Rarely, the error persists. If in doubt, try simply clicking a link rather than opening it in a new tab. Most of the time this resolve the issue you note (at least for me).