diff --git a/modules/purge_queuer_coretags/src/CacheTagsQueuer.php b/modules/purge_queuer_coretags/src/CacheTagsQueuer.php
index 7246698..8361be3 100644
--- a/modules/purge_queuer_coretags/src/CacheTagsQueuer.php
+++ b/modules/purge_queuer_coretags/src/CacheTagsQueuer.php
@@ -97,7 +97,7 @@ class CacheTagsQueuer implements CacheTagsInvalidatorInterface, ContainerAwareIn
         // Check the tag against the blacklist and skip if it matches.
         $blacklisted = FALSE;
         foreach ($this->blacklistedTagPrefixes as $prefix) {
-          if (strpos($tag, $prefix) !== FALSE) {
+          if (strpos($tag, $prefix) === 0) {
             $blacklisted = TRUE;
           }
         }