1. Define a custom AggregateFunction for a column 2. Group on a column 3. A calculation on the AggregateFunction is invoked 3. The Grouping.Key (of the input parameter) corresponds to the correct key 4. Edit a value on the column (having the AggregateFunction) 5. A calculation is invoked, but the Grouping.Key is "1" and not the correct key.