Iterator seems to be losing data java

I've got a method that returns a list of hashmaps (the data comes from a ResultSet). While trying to use an iterator to loop through the data and convert it to a String array, I was finding that the code was not working - It seemed to be losing half of my array data while doing the loop.

When swapping it to use a for loop rather than an iterator, the data was not lost. I tried using both an Iterator() and ListIterator() to no avail

Here is my original code (that wasn't working):

public String[][] getLayoutEdges() throws SQLException {
    ArrayList<String[]> returnArray = new ArrayList<>();

    List<HashMap> layoutEdges = db.getLayoutEdgesFromDatabase();
    ListIterator<HashMap> edgesIterator = layoutEdges.listIterator();

    while(edgesIterator.hasNext()) {
        ArrayList<String> tmpList = new ArrayList<>();
        tmpList.add(edgesIterator.next().get("fromnode").toString());
        tmpList.add(edgesIterator.next().get("tonode").toString());
        tmpList.add(edgesIterator.next().get("distance").toString());

        String[] tmpStr = new String[tmpList.size()];
        returnArray.add(tmpList.toArray(tmpStr));

    } 

    String[][] rtn = new String[returnArray.size()][returnArray.size()];
    return returnArray.toArray(rtn);
}

Here is the code that does work:

public String[][] getLayoutEdges() throws SQLException {
    ArrayList<String[]> returnArray = new ArrayList<>();

    List<HashMap> layoutEdges = db.getLayoutEdgesFromDatabase();

    for(HashMap tmp : layoutEdges) {
        ArrayList<String> tmpList = new ArrayList<>();
        tmpList.add(tmp.get("fromnode").toString());
        tmpList.add(tmp.get("tonode").toString());
        tmpList.add(tmp.get("distance").toString());

        String[] tmpStr = new String[tmpList.size()];
        returnArray.add(tmpList.toArray(tmpStr));
    }

    String[][] rtn = new String[returnArray.size()][returnArray.size()];
    return returnArray.toArray(rtn);
}

Can anybody tell me why the iterator wasn't working? I'm okay with using a for loop, i just can't for the life of me work out why the original iterator code I wrote wasn't keeping all my data. Wondering if there's a step i'm missing or whether I was trying to use the wrong solution.