Fernando…
Yes, I just checked. so-css is from the plugin SiteOrigin CSS. I disabled it, and the problem was resolved. It was working before the Generatepress update. However, WooCommerce also had an update at the same time. I’m hiding the “Add to Cart” button. I put the CSS into the additional CSS under customizer instead, and it works fine there. SiteOrigin CSS is a pretty popular 5-star plugin that I wanted to use for a client’s benefit.
Thanks for your help!
Gary