Hi pdfjs team,

Please find attach a really simple pdf file to reproduce the issue.
[Date.pdf](https://github.com/mozilla/pdf.js/files/8242310/Date.pdf)
This pdf contains 4 date fields, One with a default format (dd/mm/yyyy) and the 3 others with custom formats:

    -  dd
    -  mm
    -  yyyy

The expected behavior is that whenever I fill dd field with 16 for instance, then when i focus out that field the value displayed is 16 but I get 01.

This happens for dd field and mm but it's working fine for dd/mm/yyyy and yyyy fields.

The initial values of the pdf are properly displayed, this happens only if I focus one of those fields.

Thank you for your time

Best regards.

},
      s: data => {
        return data.seconds.toString();
      },
      tt: data => {
        return data.hours < 12 ? "am" : "pm";
      },
      t: data => {
        return data.hours < 12 ? "a" : "p";
      },
    };
    const data = {
      year: oDate.getFullYear(),
      month: oDate.getMonth(),
      day: oDate.getDate(),
      dayOfWeek: oDate.getDay(),
      hours: oDate.getHours(),
      minutes: oDate.getMinutes(),
      seconds: oDate.getSeconds(),
    };
    const patterns =
      /(mmmm|mmm|mm|m|dddd|ddd|dd|d|yyyy|yy|HH|H|hh|h|MM|M|ss|s|tt|t|\\.)/g;
    return cFormat.replace(patterns, function (match, pattern) {
      if (pattern in handlers) {
        return handlers[pattern](data);
      }
      return pattern.charCodeAt(1);
    });
  }
  printx(cFormat, cSource) {