The active tab is set in woocommerce/assets/js/frontend/single-product.js. Starting at line 11 this file looks for the words “comments” “reviews” or “tab-reviews” in the page url, and if found, it uses jQuery to click on the review tab. Since there is no review tab anymore, nothing gets clicked.
To solve this issue I overrode WooCommerce’s single-product.js file by enqueue-ing a new js file under/after WC’s single-product-min.js in the footer. I just copied the whole file into my theme and replaced “li.reviews_tab a” with “li.description_tab a” on lines 19 and 21. Not the most eloquent solution, but it worked for me.