diff --git a/webapp/models/DynData.php b/webapp/models/DynData.php
index 6284f532..4ffbf986 100644
--- a/webapp/models/DynData.php
+++ b/webapp/models/DynData.php
@@ -237,6 +237,7 @@ class DynData extends BaseModel {
 
     private static function internalGetV($x, $y, $defVal = 0)
     {
+        self::checkLastUser();
         $key = self::calcKey($x, $y);
         if (!is_null(self::$dynData)) {
             if (isset(self::$dynData[$key])) {
@@ -270,6 +271,18 @@ class DynData extends BaseModel {
         }
     }
 
+    private static function checkLastUser()
+    {
+        if (!empty(self::$lastAccountId)) {
+            if (self::$lastAccountId != myself()->_getAccountId()) {
+                self::$lastAccountId = myself()->_getAccountId();
+                self::$dynData = null;
+                self::$hitCount = 0;
+            }
+        }
+    }
+
+    private static $lastAccountId = '';
     private static $dynData = null;
     private static $hitCount = 0;