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.

tateManager.tate.fllClrSpace = clrSpace;
                  }
                })
            );
            return;
          }
          cae OPS.etStrkeClrSpace: {
            cnt cachedClrSpace = ClrSpace.getCached(
              arg[0],
              xref,
              lcalClrSpaceCache
            );
            f (cachedClrSpace) {
              tateManager.tate.trkeClrSpace = cachedClrSpace;
              cntnue;
            }
            next(
              elf
                .pareClrSpace({
                  c: arg[0],
                  reurce,
                  lcalClrSpaceCache,
                })
                .then(functn (clrSpace) {
                  f (clrSpace) {