Attach (recommended) or Link to PDF file here:
https://www.canada.ca/content/dam/ircc/migration/ircc/english/pdf/kits/forms/eimm5669e.pdf
[eimm5669e.pdf](https://github.com/mozilla/pdf.js/files/7225677/eimm5669e.2.pdf)

Configuration:
- Web browser and its version: Firefox nightly
- Operating system and its version: Linux Debian

Steps to reproduce the problem:
1. Look at the bottom of page 2

const assist = obj.assist;
  if (assist) {
    const assistTitle = assist[$toHTML]();
    if (assistTitle) {
      attributes.title = assistTitle;
    }
    const role = assist.role;
    const match = role.match(HEADING_PATTERN);
    if (match) {
      const ariaRole = "heading";
      const ariaLevel = match[1];
      attributes.role = ariaRole;
      attributes["aria-level"] = ariaLevel;
    }
  }
  
  
  if (obj.layout === "table") {