I have a function that is supposed to only run when called by a menu click. But it is being executed many many times, and even without even clicking on the menu item on the sheet itself.

I originally had this function as a custom function to be executed on the target sheet as a formula in a cell (=extractFormulas(parm)), but decided that it would be more efficient to call it only once (from a menu) and iterate through the rows in question, writing the results in the sheet using setValue(result). But somehow it seems as if the sheet has a memory and executes it as a cell custom function.

function onOpen() {    //create menu item
  var ui = SpreadsheetApp.getUi();
  ui.createMenu('Reconcile_Bank')
    .addItem('Get amounts from bank', 'extractFormulas')
    .addToUi();
}

function extractFormulas() {
  Logger.log('*********Starting extractFormulas()************');
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Jan");
  const lrow = sheet.getLastRow();
  const receiptsRange = sheet.getRange("C5:C" + lrow);
  var budgetEntries = receiptsRange.getValues();
  var budgetFormulas = receiptsRange.getFormulas();
  var result = '';
  var amount = 0;
  var idx = '';

  for (j=29; j<lrow; j++) {
    result = '';
    amount = sheet.getRange(j,12).getValue();
    Logger.log('row: '+ j + ' amount: '+ amount);
    if (amount = 0) continue;
    if (amount > 0) 
      result = 'deposit';
    else {
      idx = budgetFormulas.findIndex(([c]) => [...c.matchAll(/b[.d]*/g)].some(([e]) => e == -amount.toString()));
      if (idx > -1) {
        result = receiptsRange.offset(idx, 0, 1, 1).getA1Notation()+"|"+receiptsRange.offset(idx, -1, 1, 1).getValue();
        Logger.log('Formula found: '+result);
        continue;    //refers to outer loop for (j=29; j<lrow; j++) {
      }
      else  //not in a formula
        for (var i = 0; i<budgetEntries.length; i++) {
          if (budgetEntries[i][0].toString() == -amount.toString()) {
            result = 'C'+(i+5)+'|'+sheet.getRange(i+5,2).getValue();
            Logger.log('non-Formula found '+ result + 'matched to '+budgetEntries[i][0].toString());
            break;  //refers to inner loop for (var i = 0; i<budgetEntries.length; i++) {
          }
        }
    } 
    if (result == '') 
      result = 'not found';
    sheet.getRange(j,9).setValue(result);
  }
  return;
}