diff --git a/gns3server/compute/base_node.py b/gns3server/compute/base_node.py
index 02d4ce0e3..a4a2ce365 100644
--- a/gns3server/compute/base_node.py
+++ b/gns3server/compute/base_node.py
@@ -1093,7 +1093,10 @@ class BaseNode:
         # mark <bpf> [tag <id>] [pcap <path>] — tag/pcap keyword pairs, any order.
         # name travels from the controller REST layer (MarkerCreate schema) but is
         # validated here too as defense-in-depth against hand-edited topology files.
-        _MARKER_NAME_RE = re.compile(r"^(?i)(?!global)[A-Za-z0-9][A-Za-z0-9_.-]*$")
+        # Note: "global-*" names are legitimate here — they come from project-level
+        # marker definitions (inherit_marker). The prefix is only forbidden at the
+        # user-facing schema layer, not at the uBridge boundary.
+        _MARKER_NAME_RE = re.compile(r"^[A-Za-z0-9][A-Za-z0-9_.-]*$")
         if not _MARKER_NAME_RE.match(name):
             raise UbridgeError(f"Invalid marker name: {name!r}")
         cmd = 'bridge add_packet_filter {bridge} {name} mark "{bpf}"'.format(
diff --git a/gns3server/controller/__init__.py b/gns3server/controller/__init__.py
index 9cfe2bcd7..edf654ec3 100644
--- a/gns3server/controller/__init__.py
+++ b/gns3server/controller/__init__.py
@@ -741,6 +741,9 @@ class Controller:
         topo_data.pop("version")
         topo_data.pop("revision")
         topo_data.pop("type")
+        # marker_definitions is restored by Project.open() from the topology
+        # file; it must not be passed to Project.__init__.
+        topo_data.pop("marker_definitions", None)
 
         if topo_data["project_id"] in self._projects:
             project = self._projects[topo_data["project_id"]]
diff --git a/gns3server/controller/link.py b/gns3server/controller/link.py
index ac1e17c94..8ac755ba6 100644
--- a/gns3server/controller/link.py
+++ b/gns3server/controller/link.py
@@ -641,7 +641,7 @@ class Link:
             "capture_compute_id": self.capture_compute_id,
             "link_type": self._link_type,
             "filters": self._filters,
-            "markers": self._persist_markers(),
+            "markers": self._markers,
             "suspend": self._suspended,
             "link_style": self._link_style,
             "wireshark": self._wireshark,
diff --git a/gns3server/controller/project.py b/gns3server/controller/project.py
index 3eeeda20a..c8c9be93f 100644
--- a/gns3server/controller/project.py
+++ b/gns3server/controller/project.py
@@ -970,7 +970,7 @@ class Project:
             marker_name = f"global-{name}"
             if marker_name in link.markers and link.markers[marker_name].get("inherited_from") == name:
                 await link.update_marker(
-                    marker_name, bpf=d["bpf"], tag=d.get("tag"), color=d.get("color")
+                    marker_name, bpf=d["bpf"], tag=d.get("tag"), color=d.get("color"), inherited=True
                 )
         self.dump()
         self.emit_notification("project.updated", self.asdict())
@@ -1410,7 +1410,6 @@ class Project:
                 "auto_start",
                 "auto_close",
                 "auto_open",
-                "marker_definitions",
                 "scene_height",
                 "scene_width",
                 "zoom",
@@ -1427,6 +1426,12 @@ class Project:
                 if val is not None:
                     setattr(self, key, val)
 
+            # marker_definitions is loaded separately (it is not a __init__ kwarg
+            # nor a simple attribute — it backs a read-only property).
+            defs = project_data.get("marker_definitions")
+            if isinstance(defs, dict):
+                self._marker_definitions = defs
+
             topology = project_data["topology"]
             for compute in topology.get("computes", []):
                 compute_id = compute.get("compute_id")
@@ -1493,10 +1498,9 @@ class Project:
             for drawing_data in topology.get("drawings", []):
                 await self.add_drawing(dump=False, **drawing_data)
 
-            # After every link is loaded, apply project-level marker definitions
-            # so inherited markers are present from the start.
-            for link in list(self._links.values()):
-                await self.apply_defs_to_new_link(link)
+            # Note: project-level marker definitions are applied to each link
+            # inside UDPLink.create() (the inheritance hook), so they are
+            # already present once links are loaded — no separate fan-out here.
 
             self.dump()
         # We catch all error to be able to roll back the .gns3 to the previous state
diff --git a/gns3server/controller/udp_link.py b/gns3server/controller/udp_link.py
index dedb92b8e..58f357960 100644
--- a/gns3server/controller/udp_link.py
+++ b/gns3server/controller/udp_link.py
@@ -147,7 +147,7 @@ class UDPLink(Link):
         self._created = True
         # New links automatically inherit every active project-level marker
         # definition so the user doesn't have to reconfigure.
-        self._project.apply_defs_to_new_link(self)
+        await self._project.apply_defs_to_new_link(self)
 
     async def update(self):
         """
@@ -391,7 +391,7 @@ class UDPLink(Link):
         self._project.emit_notification("link.updated", self.asdict())
         self._project.dump()
 
-    async def update_marker(self, name, bpf=None, tag=None, enabled=None, color=None):
+    async def update_marker(self, name, bpf=None, tag=None, enabled=None, color=None, inherited=False):
         """
         Update an existing marker's BPF/tag/enabled/color. Any change pushes via
         ``self.update()``; uBridge picks up the new params on the next NIO
@@ -402,13 +402,15 @@ class UDPLink(Link):
         :param tag: new tag id (None = keep existing)
         :param enabled: toggle (None = keep existing)
         :param color: new hex color (None = keep existing)
+        :param inherited: set by project-level sync to bypass the inheritance
+            guard (the project layer is the legitimate editor)
         """
 
         marker_info = self._markers.get(name)
         if not marker_info:
             raise ControllerNotFoundError(f"Marker '{name}' not found on link {self._id}")
 
-        if marker_info.get("inherited_from"):
+        if marker_info.get("inherited_from") and not inherited:
             raise ControllerError(
                 f"Marker '{name}' is inherited from the project-level "
                 f"definition '{marker_info['inherited_from']}'. "