Javafx: TableCell NullpointerException

Question

I am wondering why do I get NPE in the following code:

@Override
public void updateItem(String item, boolean empty) {
    if(empty){
        super.updateItem(item, empty);
        return;
    }
    MyTableRow currentRow = (MyTableRow) getTableRow().getItem();
    currentRow.stringProperty(); // here I get NPE
}

The code snippet is from a custom TableCell, where the updateItem is overridden. At the commented line I get NPE, while the item is not null, and also empty is false. For me that means there is a row, so the getTableRow().getItem() should not be null. That is true and is a solution(or an unnecessary workaround?) to make a nullcheck after I get the item's reference, but I think that is unnecessary. Did I missed or this is an expected outcome?