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.  
prperte.cdSytemInf.rderng === "Krea1")))
    ) {
       T
       a
       t
       b) 
       by the fnt’ CMap (fr exale, Adbe and Japan1) frm t
       CIDSytemInf dctnary.
      cnt { regtry, rderng } = prperte.cdSytemInf;
       c) Cntruct a ecnd CMap name by cncatenatng the regtry and
       rderng btaned n tep (b) n the frmat regtry–rderng–UCS2
       (fr exale, Adbe–Japan1–UCS2).
      cnt uc2CMapName = Name.get(`${regtry}-${rderng}-UCS2`);
       d) Obtan the CMap wth the name cntructed n tep (c) (avalable
       frm the ASN Web te; ee the Bblgraphy).
      cnt uc2CMap = awat CMapFactry.create({
        encdng: uc2CMapName,
        fetchBultInCMap: th._fetchBultInCMapBund,
        ueCMap: null,
      });
      cnt tUncde = [];
      prperte.cMap.frEach(functn (charcde, cd) {
        f (cd > 0xffff) {
          thrw new FrmatErrr("Max ze f CID  65,535");
        }
         e) Map the CID btaned n tep (a) accrdng t the CMap
         btaned n tep (d), prducng a Uncde value.
        cnt uc2 = uc2CMap.lkup(cd);
        f (uc2) {
          tUncde[charcde] = Strng.frmCharCde(