Issue #3035140 by malcolm_p, nace_fric: Blocks plugin calls $block->build() twice

src/Plugin/ContextReaction/Blocks.php

@@ -242,12 +242,6 @@ class Blocks extends ContextReactionPluginBase implements ContainerFactoryPlugin
           ],
         ];
 
-        // Add contextual links to block.
-        $content = $block->build();
-        if (isset($content['#contextual_links'])) {
-          $blockBuild['#contextual_links'] = $content['#contextual_links'];
-        }
-
         // Add additional contextual link, for editing block configuration.
         $blockBuild['#contextual_links']['context_block'] = [
           'route_parameters' => [