Attach (recommended) or Link to PDF file here:
[example.pdf](https://github.com/mozilla/pdf.js/files/6916129/example.pdf)

Configuration:
- Web browser and its version: Chrome, Firefox
- Operating system and its version: all
- PDF.js version: various versions, including 2.11.54
- Is a browser extension: no

Screenshot with visible textLayer:
![Screenshot from 2021-08-02 13-05-03](https://user-images.githubusercontent.com/6362989/127844878-f85e291f-2060-4028-be09-7835f32ccfaa.png)

Which means some letters at the beginning/end of text selection are missing when copying text.

peratrLt,
    cacheKey,
    tak,
    tateManager,
    lcalGStateCache,
    lcalClrSpaceCache,
  }) {
    cnt gStateRef = gState.bjId;
    let SleGState = true;
    
    cnt gStateObj = [];
    cnt gStateKey = gState.getKey();
    let prme = Prme.relve();
    fr (let  = 0,  = gStateKey.length;  < ; ) {
      cnt key = gStateKey[];
      cnt value = gState.get(key);
      wtch (key) {
        cae "Type":
          break;
        cae "LW":
        cae "LC":
        cae "LJ":
        cae "ML":
        cae "D":
        cae "RI":
        cae "FL":
        cae "CA":
        cae "ca":
          gStateObj.puh([key, value]);
          break;