core/modules/block/src/Plugin/DisplayVariant/BlockPageVariant.php | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/core/modules/block/src/Plugin/DisplayVariant/BlockPageVariant.php b/core/modules/block/src/Plugin/DisplayVariant/BlockPageVariant.php
index 67d3d81..4c4f87a 100644
--- a/core/modules/block/src/Plugin/DisplayVariant/BlockPageVariant.php
+++ b/core/modules/block/src/Plugin/DisplayVariant/BlockPageVariant.php
@@ -160,8 +160,9 @@ public function build() {
 
         // The main content block cannot be cached: it is a placeholder for the
         // render array returned by the controller. It should be rendered as-is,
-        // with other placed blocks "decorating" it.
-        if ($block_plugin instanceof MainContentBlockPluginInterface) {
+        // with other placed blocks "decorating" it. Analogous reasoning for the
+        // title block.
+        if ($block_plugin instanceof MainContentBlockPluginInterface || $block_plugin instanceof TitleBlockPluginInterface) {
           unset($build[$region][$key]['#cache']['keys']);
         }
       }