IE saving server calls?

Hi experts.

This is a weird one.

I have a form wich makes AJAX calls to the server to obtain certain data on an event. I've just found that IE don't actually makes the call when it has done before, this behaviour persist until I close the browser. Firefox and Chrome works fine.

I'll try to explain myself more deeply.

The form has a dropdownlist with a list of workers. When I choose a worker, an AJAX call to the server is cast to obtain certain worker data from the database.

Ok, if I open IE and select a worker from the dropdownlist, the method on the server is called, if I select another one the method is called, BUT if I select again the first worker selected, the server method is not called again. If I select a new one the method is called, but if I select one that has been already selected before the function is not called (I check this with VS debugger, so I can actually detect that the method is being called or not).

Doesn't matter if I get out of the form and browse the rest of the application, even doesn't matter if I logout the application and log on again, while the window is open the method is somewhat recognized and "remembered". And I say remembered because, although the method not being called, the execution of the client code continues and the data received on the first call is loaded ^_^¿

So Firefox and Chrome calls the server method on each single event execution, while IE seems to identify when the call is somewhat "cached", and, instead of calling again the server it directly returns the previous value.

I can see the point in this type of behaviour but also think it has more hindrances than advantages.

Anyone had found similar behaviour and knows if it's avoidable in any way? I've tested it on IE9 and IE10.

Thanks in advance.