This is a duplicate question to: https://www.question2answer.org/qa/34458/category-page-sort-by-votes-score?show=34458
I found that if you switch on the QA_ALLOW_UNINDEXED_QUERIES value in your qa-config.php. Then Q&A will magically enable sorting on the categories.
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.
Jan 12, 2019: Q2A 1.8.3 released!