The new structured data functionality was a great addition in the new version of osclass, which is great for social sharing. However, the blog plugin does not generate the tags at all and when sharing posts to social networks it picks up the generic site name/description and image.
In oc-include/osclass/structured_data.php
Change this
<meta property="og:title" content="<?php echo osc_esc_html(osc_is_ad_page() ? osc_item_title() : osc_page_title()); ?>" />
<meta property="og:description" content="<?php echo osc_esc_html(osc_is_ad_page() ? osc_highlight(osc_item_description(), 200) : osc_page_description()); ?>" />
To this:
<meta property="og:title" content="<?php meta_title(); ?>" />
<meta property="og:description" content="<?php echo osc_esc_html(osc_is_ad_page() ? osc_highlight(osc_item_description(), 200) : meta_description()); ?>" />
To get the featured image from the blog post, see the below answer given my MB_themes.