diff --git a/src/python/WMComponent/WorkflowUpdater/WorkflowUpdaterPoller.py b/src/python/WMComponent/WorkflowUpdater/WorkflowUpdaterPoller.py
index da61c69f8a..1df1540927 100644
--- a/src/python/WMComponent/WorkflowUpdater/WorkflowUpdaterPoller.py
+++ b/src/python/WMComponent/WorkflowUpdater/WorkflowUpdaterPoller.py
@@ -271,9 +271,15 @@ def algorithm(self, parameters=None):
             with CodeTimer("Rucio block resolution", logger=logging):
                 self.findRucioBlocks(uniqueActivePU, msPileupList)
 
-            # loop over existing pileup names and
+            # loop over existing pileup names and compose list of ones we need to adjust
+            pileupList = []
+            for rec in puWflows:
+                for spec in msPileupList:
+                    if spec['pileupName'] == rec['name']:
+                        pileupList.append(spec)
             # find the json files in the spec/sandbox area and tweak them
-            self.adjustJSONSpec(msPileupList)
+            self.adjustJSONSpec(pileupList)
+#             self.adjustJSONSpec(msPileupList)
         except Exception as ex:
             msg = f"Caught unexpected exception in WorkflowUpdater. Details:\n{str(ex)}"
             logging.exception(msg)
@@ -309,6 +315,9 @@ def adjustJSONSpec(self, msPileupList):
 
             # construct jdict={"path-to-json1": jdoc1, "path-to-json2": jdoc2}
             jdict = {}
+            # TODO: verify that we do not overdo this for all pileup conf files
+            # please see Alans' concern here:
+            # https://github.com/dmwm/WMCore/pull/11884#discussion_r1479196670
             for fname in pileupConfFiles:
                 jdoc = extractPileupconf(tfile, fname)
                 bdict = blockLocations(jdoc)
@@ -320,7 +329,7 @@ def adjustJSONSpec(self, msPileupList):
                     continue
 
                 self.logger.info("Update pileup configureation file %s", fname)
-                updateBlockInfo(jdoc, rdict, bdict)
+                jdoc = updateBlockInfo(jdoc, rdict, bdict)
                 jdict[fname] = jdoc
 
             # replace pileupconf.json files within tarball