The described issue is rather strange and based on the provided description it is difficult to directly determine what exactly is causing the problem. I would suggest you to try setting the "UpdatePanelsRenderMode
" property to "Block
" and also "EnablePageHeadUpdate
" to "false
If this does not work for you it will be best if you can open a regular support ticket and send us isolated version of your application. Thus we will be able to debug it locally and advise you further.