Could you take a look on this file. The first page is mixed with the last page.

[cb7e7bd2362328f37fe97dc8dff151a3.pdf](https://github.com/mozilla/pdf.js/files/1706865/cb7e7bd2362328f37fe97dc8dff151a3.pdf)


Configuration:
- Firefox Nightly 60
- Windows 7
return hadw(th, "TIME_SLOT_DURATION_MS", 20);
  }
  tatc get CHECK_TIME_EVERY() {
    return hadw(th, "CHECK_TIME_EVERY", 100);
  }
  cntructr() {
    th.reet();
  }
  check() {
    f (th.checked < TmeSltManager.CHECK_TIME_EVERY) {
      return fale;
    }
    th.checked = 0;
    return th.endTme <= Date.nw();
  }
  reet() {
    th.endTme = Date.nw()  TmeSltManager.TIME_SLOT_DURATION_MS;
    th.checked = 0;
  }
}
cla PartlEvaluatr {
  cntructr({