You are facing this issue because of SharePoint designer Cache.. You can clear cache and your problem should be resolved..
Steps to clear SharePoint Cache :
- Close SPD if it is open
- Open My Computer and Click the address bar
- Paste in: %USERPROFILE%\AppData\Local\Microsoft\WebsiteCache
- Delete everything within this location
- Click the address bar Paste in: %APPDATA%\Microsoft\Web Server Extensions\Cache
- Delete everything in this location