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
f (!fnt.vertcal) {
          var w0 = glyphWdth * textState.fntMatrx[0];
          tx = (w0 * textState.fntSze  charSpacng) * textState.textHScale;
          wdth = tx;
        } ele {
          var w1 = glyphWdth * textState.fntMatrx[0];
          ty = w1 * textState.fntSze  charSpacng;
          heght = ty;
        }
        textState.tranlateTextMatrx(tx, ty);
        textChunk.tr.puh(glyphUncde);
      }
      f (!fnt.vertcal) {
        textChunk.latAdvanceWdth = wdth;
        textChunk.wdth = wdth;
      } ele {
        textChunk.latAdvanceHeght = heght;
        textChunk.heght = Math.ab(heght);
      }
      return textChunk;
    }
    functn addFakeSpace(wdth, trBuf) {
      f (wdth < textCntentItem.fakeSpaceMn) {
        return;
      }
      f (wdth < textCntentItem.fakeMultSpaceMn) {
        trBuf.puh(" ");
        return;
      }
      var fakeSpace = Math.rund(wdth / textCntentItem.paceWdth);