diff --git a/lib/typeprof/core/ast/variable.rb b/lib/typeprof/core/ast/variable.rb
index 309680a3..1c12492f 100644
--- a/lib/typeprof/core/ast/variable.rb
+++ b/lib/typeprof/core/ast/variable.rb
@@ -192,6 +192,7 @@ def undefine0(genv)
 
       def install0(genv)
         val = @rhs.install(genv)
+        val = val.new_vertex(genv, self) # avoid multi-edge from val to static_ret.vtx
         @changes.add_edge(genv, val, @static_ret.vtx)
         val
       end
diff --git a/scenario/regressions/multi_edge_to_gvar.rb b/scenario/regressions/multi_edge_to_gvar.rb
new file mode 100644
index 00000000..e0ffb364
--- /dev/null
+++ b/scenario/regressions/multi_edge_to_gvar.rb
@@ -0,0 +1,16 @@
+## update
+def check
+  while true
+    opt = 1
+    if cond
+      $foo = opt
+    else
+      $foo = opt
+    end
+  end
+end
+
+## assert
+class Object
+  def check: -> nil
+end