I want to add some text strings to PDFs using reportlab.
The strings look like this: 663-9999.

I’m looping over a list of users, where each user['joinCode'] is the string described above.

The actual code is:

for user in user_join_codes:
    print(f"Creating flyer for user {user['firstName']}")
    output_pdf = PdfWriter()

    qr_image = make_qr_code_image(user['joinCode'])

    qr_pdf = image_to_pdf(qr_image)

    for page_num in range(len(flyer_empty.pages)):
        page = flyer_empty.pages[page_num]

        if page_num == 1:
            code = user['joinCode']
           
            # RELEVANT code block for adding text
            packet = BytesIO()
            can = canvas.Canvas(packet, pagesize=(595, 421))
            can.setFillColorRGB(14/256, 36/256, 55/256)
            can.setFont("Helvetica", 10)
            can.drawString(507, 210, code)
            can.save()

            packet.seek(0)
            text_pdf = PdfReader(packet)
            page.merge_page(text_pdf.pages[0])
            # END BLOCK FOR ADDING TEXT

            page.merge_transformed_page(
                qr_pdf.pages[0], ctm=scale_and_translate)

        output_pdf.add_page(page)

The result is:

663- is always rendered correctly, the other digits are always garbled.

• Removing 663- from the string still renders the other digits like this
• Removing the last digits and keeping 663- renders 663- correctly
• Adding a string to the end of the code renders like in the screenshot followed by the new string e.g. 663-{garbled} foo
• Selecting and copying the garbled numbers from the PDF shows it’s 3670605810382647614253575417292383967641815316908283763829597428782587468021373564105610263482174716208958528373575306731259504502702539247632493843278497248058314298480108701980652914868025692567809415493570945694238969316393846459416740923416281376970508643461386369314240739483819462595736730797362575805701839621891891730529808108534358697316873269848203864868967491626858676913462017584909895258406141952753195898169609373659157274296 (or a similar sequence of numbers)
• using drawString on any other random string e.g. 'hello world' works without a problem
• The type(user['joinCode']) is <class 'str'>
• print(code) prints the correct string e.g. 663-9999 in the terminal

How can I make sure those digits show up correctly?