Why is this getting the same row twice in second loop? - for-loop

Question

The code below runs with no apparent errors, but despite I've looked for all possible causes I could think of, I couldn't find the reason why it gets the correct row iterated, marks it as processed ("Sim), and from the 2º iteration on, it gets the new row, but repeats the others already iterated over.
function formToData() {
var sheet = SpreadsheetApp.getActiveSpreadsheet();
var ss = sheet.getSheetByName("Form Responses 1");
var targetSheet = sheet.getSheetByName("Cadastro de Cliente");
var StartRow = 2;
var RowRange = ss.getLastRow() - StartRow + 1;
var WholeRange = ss.getRange(StartRow, 1, RowRange, 30);
var AllValues = WholeRange.getValues();
var message = "";
for (var i = 0; i < AllValues.length; i++) {
var currentRow = AllValues[i];
//if row has been sent, then continue to next iteration
if (currentRow[0] != "" && currentRow[29] != "Sim") {
//set the row to look at
var setRow = parseInt(i) + StartRow;
var data = currentRow[0];
var dataFormatted = Utilities.formatDate(data, SpreadsheetApp.getActive().getSpreadsheetTimeZone(), "dd/MM/yyyy', às 'HH:mm") + "hs";
//set HTML template for information
message +=
"<p><b>Data: </b>" + dataFormatted + "</p>" +
"<p><b>Unidade: </b>" + currentRow[1] + "</p>"
//mark row as "sent"
ss.getRange(setRow, 30).setValue("Sim");
var values = targetSheet.getRange("A:A").getValues();
var maxIndex = values.reduce(function (maxIndex, row, index) {
return row[0] === "" ? maxIndex : index;
}, 0);
targetSheet.getRange(maxIndex + 2, 1, 1, 30)
.setNumberFormat("#")
.setValues([currentRow]);
var sendTo = "email";
var subject = "Cadastro de cliente novo";
if (message) {
MailApp.sendEmail({
to: sendTo,
subject: subject,
name: "Comercial - Emape",
htmlBody: message,
});
}
}
}//For loop closes
}
I'd appreaciate if you could help me find the flaw.

Answer 1

I tried to replicate this behavior, however, on a static sheet the script performs as expected:
Set unmarked rows in column 30 as 'Sim'.
Copy these rows to a separate sheet starting from the first empty row (or whichever row that Column A is empty).
Given the names of the functions and the sheets, this may be a Sheet generated by a Google Form. These sheets are dynamic, and there is a possibility that the contents may change while your script is running, especially if users are allowed to edit responses.
As a workaround, I suggest to lock the form before running the script:
Also, check the contents of the sheet and form for any possibility that the "Sim" mark might be overwritten by new or edited form data, maybe the sheet is inserting 30 columns instead of 29 or less.