Log Entry View and other settings pages don't load (5.18.4, Drupal 7.67)
Welcome to Stack Exchange!  I'm tempted to mark this question as a duplicate to point you to existing answers - but I'm struggling to find the "one true answer". templates_c cache files not being deleted is close.  Essentially, it sounds like something created a file in templates_c that's not readable by the web server user.  The quick solution is to delete the templates_c folder - this is always safe and it will regenerate.  However, in the longer term you need to find what caused the problem.  Are you running cron as a user other than the web server/PHP user?  Are you running drush from the command line as a user with different permissions?  If you don't find the solution the problem will keep coming back.