Symptoms
A smartform with a list view works properly until the refresh button is pressed. An error message stating "Key couldn't be found in the collection." is generated.
Diagnoses
We were able to reproduce the issue and has been identified as bug.
Resolution
A new TFS item has been created to address this in the Next release of K2. As for the moment there is no workaround for this. Using a different property to filter instead of using the associated property would work as the workaround.