diff --git a/classes/admin.php b/classes/admin.php
index 366490fb..7fc59123 100644
--- a/classes/admin.php
+++ b/classes/admin.php
@@ -1024,49 +1024,49 @@ class Admin
     {
         static $guess;
 
-        if (!$guess) {
+        if (!isset($guess[$date])) {
             if (Utils::contains($date, '/')) {
                 if ($this->validateDate($date, 'm/d/Y H:i')) {
-                    $guess = 'm/d/Y H:i';
+                    $guess[$date] = 'm/d/Y H:i';
                 } elseif ($this->validateDate($date, 'm/d/y H:i')) {
-                    $guess = 'm/d/y H:i';
+                    $guess[$date] = 'm/d/y H:i';
                 } elseif ($this->validateDate($date, 'm/d/Y G:i')) {
-                    $guess = 'm/d/Y G:i';
+                    $guess[$date] = 'm/d/Y G:i';
                 } elseif ($this->validateDate($date, 'm/d/y G:i')) {
-                    $guess = 'm/d/y G:i';
+                    $guess[$date] = 'm/d/y G:i';
                 } elseif ($this->validateDate($date, 'm/d/Y h:ia')) {
-                    $guess = 'm/d/Y h:ia';
+                    $guess[$date] = 'm/d/Y h:ia';
                 } elseif ($this->validateDate($date, 'm/d/y h:ia')) {
-                    $guess = 'm/d/y h:ia';
+                    $guess[$date] = 'm/d/y h:ia';
                 } elseif ($this->validateDate($date, 'm/d/Y g:ia')) {
-                    $guess = 'm/d/Y g:ia';
+                    $guess[$date] = 'm/d/Y g:ia';
                 } elseif ($this->validateDate($date, 'm/d/y g:ia')) {
-                    $guess = 'm/d/y g:ia';
+                    $guess[$date] = 'm/d/y g:ia';
                 }
             } elseif (Utils::contains($date, '-')) {
                 if ($this->validateDate($date, 'd-m-Y H:i')) {
-                    $guess = 'd-m-Y H:i';
+                    $guess[$date] = 'd-m-Y H:i';
                 } elseif ($this->validateDate($date, 'd-m-y H:i')) {
-                    $guess = 'd-m-y H:i';
+                    $guess[$date] = 'd-m-y H:i';
                 } elseif ($this->validateDate($date, 'd-m-Y G:i')) {
-                    $guess = 'd-m-Y G:i';
+                    $guess[$date] = 'd-m-Y G:i';
                 } elseif ($this->validateDate($date, 'd-m-y G:i')) {
-                    $guess = 'd-m-y G:i';
+                    $guess[$date] = 'd-m-y G:i';
                 } elseif ($this->validateDate($date, 'd-m-Y h:ia')) {
-                    $guess = 'd-m-Y h:ia';
+                    $guess[$date] = 'd-m-Y h:ia';
                 } elseif ($this->validateDate($date, 'd-m-y h:ia')) {
-                    $guess = 'd-m-y h:ia';
+                    $guess[$date] = 'd-m-y h:ia';
                 } elseif ($this->validateDate($date, 'd-m-Y g:ia')) {
-                    $guess = 'd-m-Y g:ia';
+                    $guess[$date] = 'd-m-Y g:ia';
                 } elseif ($this->validateDate($date, 'd-m-y g:ia')) {
-                    $guess = 'd-m-y g:ia';
+                    $guess[$date] = 'd-m-y g:ia';
                 }
             } else {
-                $guess = 'd-m-Y H:i';
+                $guess[$date] = 'd-m-Y H:i';
             }
         }
 
-        return $guess;
+        return $guess[$date];
     }
 
     public function validateDate($date, $format)