HTML validation error

Just installed the WP show more plugin. It looks good & works great. But a validation error shows for the places I put [show_more more=”read more” less=”read less”]

The HTML error is: No p element in scope but a p end tag seen.

Here is the error that shows in red in the source code: <div class=”show_more”><p class=”wpsm-show” style=”color: #cc0000; font-size: 100%; text-align: left;”> read more</p><div class=”wpsm-content”> </p>

Help appreciated.