Index: src/wp-includes/template-loader.php
===================================================================
--- src/wp-includes/template-loader.php	(revision 60000)
+++ src/wp-includes/template-loader.php	(working copy)
@@
 if ( is_tax() ) {
 	$term = get_queried_object();
 
 	if ( $term && ! is_wp_error( $term ) ) {
 		$templates = array();
 
-		$templates[] = "taxonomy-{$term->taxonomy}-{$term->slug}.php";
+		// Add new template based on term_id for better stability when slugs change.
+		$templates[] = "taxonomy-{$term->taxonomy}-{$term->term_id}.php";
+		$templates[] = "taxonomy-{$term->taxonomy}-{$term->slug}.php";
 		$templates[] = "taxonomy-{$term->taxonomy}.php";
 		$templates[] = 'taxonomy.php';
 		$templates[] = 'archive.php';
 
 		$template = locate_template( $templates );
 		if ( $template ) {
 			load_template( $template );
 			return;
 		}
 	}
 }