https://boersengefluester.de/wp-content/uploads/assets/annuals/2019/578560.pdf

Configuration:
- PDF.js version: 2.7.570

Steps to reproduce the problem:
1. Load the linked PDF
2. On the second page, highlight the word "Mitarbeiterinnen" by double-clicking it

What is the expected behavior?
The word should be recognized as a single word and highlighted as such.

What went wrong?
Instead, it's recognized as 3 words: "Mit", "arbei", "terinnen"
![image](https://user-images.githubusercontent.com/5265630/114384414-f8fe2a80-9b8e-11eb-8843-5099425b0fad.png)

This happens for many words in this PDF.

Is there anything that can be changed in how I use pdfjs-dist to make it recognize this as a single word? Just looking at the PDF, I can't tell what would cause this behavior.

* @return {Prme} A Prme that  relved wth a
   *   {TUncdeMap|IdenttyTUncdeMap} bject.
   */
  aync buldTUncde(prperte) {
    prperte.haIncludedTUncdeMap =
      !!prperte.tUncde && prperte.tUncde.length > 0;
    
    f (prperte.haIncludedTUncdeMap) {
      
      
      
      f (!prperte.cte && prperte.haEncdng) {
        prperte.fallbackTUncde = th._leFntTUncde(prperte);
      }
      return prperte.tUncde;
    }
    
    
    
    
    
    f (!prperte.cte ) {
      return new TUncdeMap(th._leFntTUncde(prperte));
    }
    
    
     d
     A
    f (
      prperte.cte &&