diff --git a/CHANGES.md b/CHANGES.md
index 5aadb908f..cebf0b98e 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -4,6 +4,7 @@
 Changes in 11.8.3
 -----------------
 - Fix SQL error escape course title & save course, not course period title in FinalGrades.inc.php
+- Fix performance: avoid silencing PHP error with @, use isset() instead in DBGet.fnc.php
 
 Changes in 11.8.2
 -----------------
diff --git a/functions/DBGet.fnc.php b/functions/DBGet.fnc.php
index 6d5213d64..6b270633c 100644
--- a/functions/DBGet.fnc.php
+++ b/functions/DBGet.fnc.php
@@ -88,7 +88,7 @@ function DBGet( $QI, $functions = [], $index = [] )
 				$ind[] = issetVal( $RET[ $col ] );
 			}
 
-			$ind_concat = implode( '', $ind );
+			$ind_concat = implode( '-', $ind );
 
 			$this_ind = isset( $s[ $ind_concat ] ) ? ++$s[ $ind_concat ] : ( $s[ $ind_concat ] = 1 );
 		}