Google app script triggering twice after Google form submit - google-apps-script

Question

I'm having issue with my script running twice in a Google Form and the linked Sheets. I have one form submit trigger. If I delete this trigger, the script doesn't run at all on a form submit. If I add the trigger back in, it will trigger twice -- but there is only one form submittal in the sheet responses. I thought that maybe I was clicking the form submittal twice, but that doesn't seem to be it. Thanks.
Here is the code:
function myFunction(e) {
// Set values for event "e" from Response form, each number being a column in the spreadsheet. Column zero is not used - it is the timestamp
var JobNumber = e.values[1];
// Create an array from the PNEZD field in the form then find the array location for the inputted shot number
var PNEZD_field = e.values[2];
var PNEZD_array = Utilities.parseCsv(PNEZD_field);
var StructureNumber = e.values[3];
for (i = 0; i < PNEZD_array.length; i++) {
if (PNEZD_array[i][0] == StructureNumber) {
var Elevation = PNEZD_array[i][3];
var Easting = PNEZD_array[i][2];
var Northing = PNEZD_array[i][1];
}
}
// STRUCTURE TYPE AND SIZE
var StructureType = e.values[4];
var StructureSize = e.values[5];
// PIPE NUMBER 1
var PipeSize1 = e.values[6];
var PipeMaterial1 = e.values[7];
var PipeDirection1 = e.values[8];
var PipeMeasureDown1 = e.values[9];
// PIPE NUMBER 2
var PipeSize2 = e.values[10];
var PipeMaterial2 = e.values[11];
var PipeDirection2 = e.values[12];
var PipeMeasureDown2 = e.values[13];
// PIPE NUMBER 3
var PipeSize3 = e.values[14];
var PipeMaterial3 = e.values[15];
var PipeDirection3 = e.values[16];
var PipeMeasureDown3 = e.values[17];
// PIPE NUMBER 4
var PipeSize4 = e.values[18];
var PipeMaterial4 = e.values[19];
var PipeDirection4 = e.values[20];
var PipeMeasureDown4 = e.values[21];
// PIPE NUMBER 5
var PipeSize5 = e.values[22];
var PipeMaterial5 = e.values[23];
var PipeDirection5 = e.values[24];
var PipeMeasureDown5 = e.values[25];
// Calculate Invert Elevations:
var Dip1 = Elevation - PipeMeasureDown1;
var Dip2 = Elevation - PipeMeasureDown2;
var Dip3 = Elevation - PipeMeasureDown3;
var Dip4 = Elevation - PipeMeasureDown4;
var Dip5 = Elevation - PipeMeasureDown5;
// Build structure information
var firstLine = StructureType + " " + StructureSize + "\n";
var secondLine = "Rim=" + Elevation + "\n";
var thirdLine = PipeSize1 + " " + PipeMaterial1 + " I.E. " + PipeDirection1 + "=" + Dip1 + "'\n";
var fourthLine = PipeSize2 + " " + PipeMaterial2 + " I.E. " + PipeDirection2 + "=" + Dip2 + "'\n";
var fifthLine = PipeSize3 + " " + PipeMaterial3 + " I.E. " + PipeDirection3 + "=" + Dip3 + "'\n";
var sixthLine = PipeSize4 + " " + PipeMaterial4 + " I.E. " + PipeDirection4 + "=" + Dip4 + "'\n";
var seventhLine = PipeSize5 + " " + PipeMaterial5 + " I.E. " + PipeDirection5 + "=" + Dip5 + "'";
var Mtext = firstLine + secondLine + thirdLine + fourthLine + fifthLine + sixthLine + seventhLine;
var calcsheet = SpreadsheetApp.openById('-removed-').getSheetByName('Calculations');
var ss = SpreadsheetApp.getActiveSpreadsheet(); // ss is now the spreadsheet the script is associated with
var sheet = ss.getSheets()[1]; // sheets are counted starting from 0
// sheet is the second worksheet in the spreadsheet
var cell = sheet.getRange("A1");
cell.setValue(Mtext);
// Dump variable to logger log
// var dump = "Variable dumps: first the URL: " + PNEZD_fileURL + " and next the file ID alone: " + PNEZD_fileID + " and now the job number: " + JobNumber;
// Logger.log( dump );
// Logger.log(JobNumber);
// Logger.log("Data dump: " + PNEZD_field);
// Logger.log("Data dump: " + PNEZD_array[3][3]);
// Logger.log(StructureNumber + "," + Northing + "," + Easting + "," + Elevation);
}