Attach (recommended) or Link to PDF file here:
[docOficialPDF.php.pdf](https://github.com/mozilla/pdf.js/files/7159923/docOficialPDF.php.pdf)

Configuration:
- Web browser and its version: Firefox nightly
- Operating system and its version: linux debian
- PDF.js version: built-in viewer
- Is a browser extension: no

Steps to reproduce the problem:
1. Open the pdf page 2
2. Checkbox "Alta" in section 2 must be checked

It works fine with evince.
if (renderForms && !(this instanceof SignatureWidgetAnnotation)) {
      return Promise.resolve(new OperatorList());
    }
    if (!this._hasText) {
      return super.getOperatorList(
        evaluator,
        task,
        renderForms,
        annotationStorage
      );
    }
    return this._getAppearance(evaluator, task, annotationStorage).then(
      content => {
        if (this.appearance && content === null) {
          return super.getOperatorList(
            evaluator,
            task,
            renderForms,
            annotationStorage
          );
        }
        const operatorList = new OperatorList();
        
        
        if (!this._defaultAppearance || content === null) {
          return operatorList;
        }