diff --git a/src/PhpSpreadsheet/Calculation/Functions.php b/src/PhpSpreadsheet/Calculation/Functions.php
index dc6ee82e..8075811f 100644
--- a/src/PhpSpreadsheet/Calculation/Functions.php
+++ b/src/PhpSpreadsheet/Calculation/Functions.php
@@ -705,8 +705,8 @@ class Functions
 
     public static function trimSheetFromCellReference(string $coordinate): string
     {
-        while (strpos($coordinate, '!') !== false) {
-            $coordinate = substr($coordinate, strpos($coordinate, '!') + 1);
+        if (strpos($coordinate, '!') !== false) {
+            $coordinate = substr($coordinate, strrpos($coordinate, '!') + 1);
         }
 
         return $coordinate;
diff --git a/src/PhpSpreadsheet/Cell/CellAddress.php b/src/PhpSpreadsheet/Cell/CellAddress.php
index d587dcd1..069c9ac9 100644
--- a/src/PhpSpreadsheet/Cell/CellAddress.php
+++ b/src/PhpSpreadsheet/Cell/CellAddress.php
@@ -47,15 +47,9 @@ class CellAddress
      */
     private static function validateColumnAndRow($columnId, $rowId): void
     {
-        $array = [$columnId, $rowId];
-        array_walk(
-            $array,
-            function ($value): void {
-                if (!is_numeric($value) || $value <= 0) {
-                    throw new Exception('Row and Column Ids must be positive integer values');
-                }
-            }
-        );
+        if (!is_numeric($columnId) || $columnId <= 0 || !is_numeric($rowId) || $rowId <= 0) {
+            throw new Exception('Row and Column Ids must be positive integer values');
+        }
     }
 
     /**