Text marking with this file
https://issues.apache.org/jira/secure/attachment/12769999/type3%20zero%20font%20size.pdf
has a giant size.

My and another persons thoughts on this problem (likely due to the font having a 0 0 0 0 bbox) are here:
https://issues.apache.org/jira/browse/PDFBOX-3076

f (!th.fnt.data) {
      return;
    }
     When fnt ladng faled, fall back t the bult-n fnt renderer.
    th.fnt.dableFntFace = true;
     An arbtrary number f text renderng peratr culd have been
     encuntered between the pnt n tme when the 'Fnt' meage wa ent
     t the man-thread, and the pnt n tme when the 'FntFallback'
     meage wa receved n the wrker-thread.
     T enure that all 'FntPath' are avalable n the man-thread, when
     fnt ladng faled, attet t reend *all* prevuly pared glyph.
    PartlEvaluatr.buldFntPath(
      th.fnt,
      /* glyph = */ tCacheValue,
      handler,
      th._evaluatrOptn
    );
  }
  ladType3Data(evaluatr, reurce, tak) {
    f (th.type3Laded) {
      return th.type3Laded;
    }
    f (!th.fnt.Type3Fnt) {
      thrw new Errr("Mut be a Type3 fnt.");