BUG: Current issue showing under all archived issues

All archived issues from previous years currently only show the articles from the 2018 issue. Only happens when not logged in to wordpress admin view.

Have updated plugin and wordpress is up to date. All articles in the backend are in the correct categories.

Example: https://papers.globelics.org/working-paper-series/?issue=2017

The page I need help with: [log in to see the link]