Astra support says can be due to cashing plugin like Sg optimizer or wp rocket ect.
If the plugin has a feature to exclude files, please try to exclude the following JS file so it won’t be delayed.
wp-content/themes/astra/assets/js/minified/frontend.min.js
wp-content/themes/astra/assets/js/minified/frontend-pro.min.js
If you are not sure how to do that, please refer to the plugin’s doc or get in touch with the plugin’s author/support.