it is probably not a bug, you have to configure your document settings in order to thumbnails be displayed on AccessPoint. Open your server document with QV Desktop, go to Document Properties->Opening tab and in Document thumbnail part select 'Opening Sheet'. Save your setting and see what happens on AccessPoint.
Ok, I have tested this and using QV.exe /r and the thumbnail is not correct. However, this is working as design. What you need to do is enable batch reloads.
1. To start open the document with QlikView and then save it. This should get the thumbnail back.
2. Go to C:\Program Files\QlikView\Distribution Service and make a backup of QVDistributionService.exe.config.
3. Edit QVDistributionService.exe.config and look for <add key="EnableBatchMode" value="false" />
change false to true and then save the file.
4. Change you batch fle to "C:\Program Files\QlikView\Distribution Service\QVDistributionService.exe" -r=C:\Documents\Presidents.qvw changing C:\Documents\Presidents.qvw to the correct path and qvw.
This will do a reload and keep the thumbnail..