diff --git a/lib/phpunit/classes/util.php b/lib/phpunit/classes/util.php
index c7f318e14dc..4f8ee14e978 100644
--- a/lib/phpunit/classes/util.php
+++ b/lib/phpunit/classes/util.php
@@ -255,6 +255,9 @@ class phpunit_util extends testing_util {
         if (class_exists('\core_course\customfield\course_handler')) {
             \core_course\customfield\course_handler::reset_caches();
         }
+        if (class_exists('\core_reportbuilder\manager')) {
+            \core_reportbuilder\manager::reset_caches();
+        }
 
         // Clear static cache within restore.
         if (class_exists('restore_section_structure_step')) {
diff --git a/reportbuilder/classes/manager.php b/reportbuilder/classes/manager.php
index 015cc3f948f..c46fe804272 100644
--- a/reportbuilder/classes/manager.php
+++ b/reportbuilder/classes/manager.php
@@ -33,9 +33,15 @@ use core_reportbuilder\local\report\base;
  */
 class manager {
 
+    /** @var base $instances */
+    private static $instances = [];
+
     /**
      * Return an instance of a report class from the given report persistent
      *
+     * We statically cache the list of loaded reports during request lifecycle, to allow this method to be called
+     * repeatedly without potential performance problems initialising the same report multiple times
+     *
      * @param report $report
      * @param array $parameters
      * @return base
@@ -43,16 +49,30 @@ class manager {
      * @throws source_unavailable_exception
      */
     public static function get_report_from_persistent(report $report, array $parameters = []): base {
-        $source = $report->get('source');
+        $instancekey = $report->get('id');
+        if (!array_key_exists($instancekey, static::$instances)) {
+            $source = $report->get('source');
 
-        // Throw exception for invalid or unavailable report source.
-        if (!self::report_source_exists($source)) {
-            throw new source_invalid_exception($source);
-        } else if (!self::report_source_available($source)) {
-            throw new source_unavailable_exception($source);
+            // Throw exception for invalid or unavailable report source.
+            if (!self::report_source_exists($source)) {
+                throw new source_invalid_exception($source);
+            } else if (!self::report_source_available($source)) {
+                throw new source_unavailable_exception($source);
+            }
+
+            static::$instances[$instancekey] = new $source($report, $parameters);
         }
 
-        return new $source($report, $parameters);
+        return static::$instances[$instancekey];
+    }
+
+    /**
+     * Run reset code after unit tests to reset the instance cache
+     */
+    public static function reset_caches(): void {
+        if (PHPUNIT_TEST) {
+            static::$instances = [];
+        }
     }
 
     /**