Iterator is "empty" after set_collection

Iterator is "empty" in get method of an attribute after set_collection is done in do prepare ouput.

For the first time when i am trying to load the values from database on Table View in web UI , its getting publish perfectly.

But as soon as i click some where else , values changes to not bound . Though i checked in getter , collection is holding the values, but iterator there is empty.

Regards,

Vishal