It's possible for a PDF page to have multiple resource dictionaries which could have patterns (shading or tiling) that have the same names. Our cache currently works off of name, so we could potentially be caching one pattern and retrieving the wrong one if the name is the same, but the resource dictionary has changed.

I'm not aware of any PDFs affected by this issue, but issue6737.pdf has an example of this with radial shadings. There are two patterns `P1` and `P2` which each have their own resource dictionaries. Each of those resource dictionaries has a pattern named `Sh0`, but they are different shadings.  
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) {