diff --git a/tests/TestHarness/Node.py b/tests/TestHarness/Node.py
index d96d5f5e29..869dd36f33 100644
--- a/tests/TestHarness/Node.py
+++ b/tests/TestHarness/Node.py
@@ -705,15 +705,44 @@ def linesInLog(self, searchStr):
                         lines.append(line)
         return lines
 
-    def countInLog(self, searchStr) -> int:
+    # Verfify that in during synching, unlinkable blocks are expected if
+    # the number of each group of consecutive unlinkable blocks is less than sync fetch span
+    def verifyUnlinkableBlocksExpected(self, syncFetchSpan) -> bool:
         dataDir=Utils.getNodeDataDir(self.nodeId)
         files=Node.findStderrFiles(dataDir)
-        count = 0
+
+        # A sample of unique line of unlinkable_block in logging file looks like:
+        # info  2024-11-14T13:48:06.038 nodeos    net_plugin.cpp:3870           process_signed_block ] unlinkable_block_exception connection - 1: #130 1d74c43582d10251...: Unlinkable block (3030001)
+        pattern = re.compile(r"unlinkable_block_exception connection - \d+: #(\d+)")
+
         for file in files:
+            blocks = []
             with open(file, 'r') as f:
-                contents = f.read()
-                count += contents.count(searchStr)
-        return count
+                for line in f:
+                    match = pattern.search(line)
+                    if match:
+                        try:
+                            blockNum = int(match.group(1))
+                            blocks.append(blockNum)
+                        except ValueError:
+                            Utils.Print(f"unlinkable block number cannot be converted into integer: in {line.strip()} of {f}")
+                            return False
+                blocks.sort() # blocks from multiple connections might be out of order
+                numConsecutiveUnlinkableBlocks = 0 if len(blocks) == 0 else 1 # numConsecutiveUnlinkableBlocks is at least 1 if len(blocks) > 0
+                for i in range(1, len(blocks)):
+                    if blocks[i] == blocks[i - 1] or blocks[i] == blocks[i - 1] + 1: # look for consecutive blocks, including duplicate
+                        if blocks[i] == blocks[i - 1] + 1: # excluding duplicate
+                            ++numConsecutiveUnlinkableBlocks
+                    else: # start a new group of consecutive blocks
+                        if numConsecutiveUnlinkableBlocks > syncFetchSpan:
+                            Utils.Print(f"the number of a group of unlinkable blocks {numConsecutiveUnlinkableBlocks} greater than syncFetchSpan {syncFetchSpan} in {f}")
+                            return False
+                        numConsecutiveUnlinkableBlocks = 1
+        if numConsecutiveUnlinkableBlocks > syncFetchSpan:
+            Utils.Print(f"the number of a group of unlinkable blocks {numConsecutiveUnlinkableBlocks} greater than syncFetchSpan {syncFetchSpan} in {f}")
+            return False
+        else:
+            return True
 
     # Verify that we have only one "Starting block" in the log for any block number unless:
     # - the block was restarted because it was exhausted,
diff --git a/tests/nodeos_startup_catchup.py b/tests/nodeos_startup_catchup.py
index 669e1d7233..00774a84ad 100755
--- a/tests/nodeos_startup_catchup.py
+++ b/tests/nodeos_startup_catchup.py
@@ -248,12 +248,8 @@ def waitForNodeStarted(node):
         # See https://github.com/AntelopeIO/spring/issues/81 for fix to reduce the number of expected unlinkable blocks
         # Test verifies LIB is advancing, check to see that not too many unlinkable block exceptions are generated
         # while syncing up to head.
-        numUnlinkable = catchupNode.countInLog("unlinkable_block")
-        numUnlinkableAllowed = 500
-        Print(f"Node{catchupNodeNum} has {numUnlinkable} unlinkable_block in {catchupNode.data_dir}")
-        if numUnlinkable > numUnlinkableAllowed:
-            errorExit(f"Node{catchupNodeNum} has {numUnlinkable} which is more than the configured "
-                      f"allowed {numUnlinkableAllowed} unlinkable blocks: {catchupNode.data_dir}.")
+        if not catchupNode.verifyUnlinkableBlocksExpected(sync_fetch_span):
+            errorExit(f"unlinkable blocks are not expected") # details already logged in verifyUnlinkableBlocksExpected
 
     testSuccessful=True