Hello,
I just disabled all plugins and the issue still exists.
I am able to adjust quantities only from the off-canvas mini cart, single product page and cart page. Quantities don’t seem to be working from the product listing pages, product category listing pages and home page widget sliders.
Also, another issue I am having is with the ajax category filters. Although I have set me product per row count to 4, whenever I click on one of the categories with ajax enabled, the product count per row goes back to 3. I’ve checked all settings and there is no option that has 3 products per row set.