I'm forced to use manual excerpts on a number of my posts to integrate them with a shortcode plugin. However, this is interfering with how they're being displayed on an archive page (using a page template). Is there a way to force WordPress to display an automated excerpt (ie, the first 80 words) on one page template only?
You can utilize the
wp_trim_excerpt filter. In your callback function that filters the the excerpt text, you can test for the presence of a certain template; then, if that template is being used, you can go ahead and alter the excerpt in any way that you see fit. In order to determine which template is being used, see this clever solution: Get name of the current template file. Let me know if this helps or if you need more.