A workaround is to remove the loading sign functionality by placing the following script at the end of the form tag

The second override is necessary only if you use the OnClientDataLoaded event to alter the data and add fields in the data object that do not exist in the server response. You need to rename the OnClientDataLoaded method call to use your actual method name.

You can find an example of both workarounds and their usage attached.

Some additional information:
- If possible, move the tiles out of the AJAX request, as this will eliminate all of the problems. Depending on the actual scenario perhaps you can make sure they are not in an update panel (e.g., position them absolutely on the page while keeping their markup out of the partial postback).
- consider moving any data formatting logic from the event handler to the template. You can define functions that format the code in the template, not only in the event. An example is available in the attached file. Alternatively, you can return the data formatted from the web service.
- consider reducing the time interval for the requests, because after the AJAX request, only 1 of 2 requests will update the tile UI.