diff --git a/src/blenderbim/blenderbim/bim/module/geometry/helper.py b/src/blenderbim/blenderbim/bim/module/geometry/helper.py
index 6f7374f80c..ef61723051 100644
--- a/src/blenderbim/blenderbim/bim/module/geometry/helper.py
+++ b/src/blenderbim/blenderbim/bim/module/geometry/helper.py
@@ -21,6 +21,7 @@ import bmesh
 import mathutils
 import ifcopenshell
 import ifcopenshell.util.unit
+import blenderbim.tool as tool
 from math import pi, pow
 from mathutils import Vector, Matrix, geometry
 from typing import Union
@@ -141,13 +142,14 @@ class Helper:
             total_groups = 0
             is_circle = False
             for group_type, group_indices in groups.items():
-                for group_index in group_indices:
-                    if group_index in vert[deform_layer]:
-                        if group_type == "IFCCIRCLE":
-                            is_circle = True
-                        group_verts[group_type].setdefault(group_index, 0)
-                        group_verts[group_type][group_index] += 1
-                        total_groups += 0
+                is_special, group_index = tool.Blender.bmesh_check_vertex_in_groups(vert, deform_layer, group_indices)
+                if not is_special:
+                    continue
+                if group_type == "IFCCIRCLE":
+                    is_circle = True
+                group_verts[group_type].setdefault(group_index, 0)
+                group_verts[group_type][group_index] += 1
+                total_groups += 0
             if total_groups > 1:  # A vert can only belong to one group
                 return (False, "AMBIGUOUS_SPECIAL_VERTEX")
             elif is_circle:
diff --git a/src/blenderbim/blenderbim/bim/module/model/decorator.py b/src/blenderbim/blenderbim/bim/module/model/decorator.py
index 72d47d3c42..080966c22d 100644
--- a/src/blenderbim/blenderbim/bim/module/model/decorator.py
+++ b/src/blenderbim/blenderbim/bim/module/model/decorator.py
@@ -23,6 +23,7 @@ from math import sin, cos, radians
 from bpy.types import SpaceView3D
 from mathutils import Vector, Matrix
 from gpu_extras.batch import batch_for_shader
+from typing import Union
 
 
 ERROR_ELEMENTS_COLOR = (1, 0.2, 0.322, 1)  # RED
@@ -35,15 +36,6 @@ def transparent_color(color, alpha=0.1):
     return color
 
 
-def bm_check_vertex_in_groups(vertex, deform_layer, groups):
-    """returns tuple boolean (whether vertex is in any of the groups)
-    and related group index"""
-    for group_index in vertex[deform_layer].keys():
-        if group_index in groups:
-            return True, group_index
-    return False, None
-
-
 class ProfileDecorator:
     installed = None
 
@@ -148,12 +140,12 @@ class ProfileDecorator:
             # deform_layer is None if there are no verts assigned to vertex groups
             # even if there are vertex groups in the obj.vertex_groups
             if deform_layer:
-                is_arc, group_index = bm_check_vertex_in_groups(vertex, deform_layer, arc_groups)
+                is_arc, group_index = tool.Blender.bmesh_check_vertex_in_groups(vertex, deform_layer, arc_groups)
                 if is_arc:
                     arcs.setdefault(group_index, []).append(vertex)
                     special_vertex_indices[vertex.index] = group_index
 
-                is_circle, group_index = bm_check_vertex_in_groups(vertex, deform_layer, circle_groups)
+                is_circle, group_index = tool.Blender.bmesh_check_vertex_in_groups(vertex, deform_layer, circle_groups)
                 if is_circle:
                     circles.setdefault(group_index, []).append(vertex)
                     special_vertex_indices[vertex.index] = group_index
diff --git a/src/blenderbim/blenderbim/tool/blender.py b/src/blenderbim/blenderbim/tool/blender.py
index a6de0de09a..a6133f8d6e 100644
--- a/src/blenderbim/blenderbim/tool/blender.py
+++ b/src/blenderbim/blenderbim/tool/blender.py
@@ -569,6 +569,18 @@ class Blender(blenderbim.core.tool.Blender):
 
         return bm_a
 
+    @classmethod
+    def bmesh_check_vertex_in_groups(
+        cls, vertex: bmesh.types.BMVert, deform_layer: bmesh.types.BMLayerItem, groups: list[int]
+    ) -> Union[tuple[Literal[True], int], tuple[Literal[False], None]]:
+        """returns tuple boolean (whether vertex is in any of the groups) and related group index"""
+        for group_index in vertex[deform_layer].keys():
+            # ignore vertex groups assignments produced by edge subdivision near arcs
+            # they usually have weight = 0.5
+            if group_index in groups and vertex[deform_layer][group_index] == 1.0:
+                return True, group_index
+        return False, None
+
     @classmethod
     def toggle_edit_mode(cls, context: bpy.types.Context) -> set:
         ao = context.active_object