diff --git a/lib/spack/spack/solver/asp.py b/lib/spack/spack/solver/asp.py
index 11340d61e5b..71ba84f2b74 100644
--- a/lib/spack/spack/solver/asp.py
+++ b/lib/spack/spack/solver/asp.py
@@ -862,11 +862,13 @@ def visit(node):
         self.control.load(os.path.join(parent_dir, "display.lp"))
         if not setup.concretize_everything:
             self.control.load(os.path.join(parent_dir, "when_possible.lp"))
-        flags = []
-        for spec in specs:
-            flags.append(spec.compiler_flags)
 
-        if self._compiler_flag_has_propagation(flags):
+
+        has_propagation = False
+        for spec in specs:
+            for dep in spec.traverse(root=True):
+                has_propagation |= self._compiler_flag_has_propagation(dep.compiler_flags)
+        if has_propagation:
             self.control.load(os.path.join(parent_dir, "propagation.lp"))
 
         timer.stop("load")
@@ -978,10 +980,9 @@ def _model_has_cycles(self, models):
         return cycle_result.unsatisfiable
 
     def _compiler_flag_has_propagation(self, flags):
-        for flag in flags:
-            for flag_type, flag_vals in flag.items():
-                if any(val.propagate for val in flag_vals):
-                    return True
+        for _, flag_vals in flags.items():
+            if any(val.propagate for val in flag_vals):
+                return True
         return False
 
 
diff --git a/lib/spack/spack/test/concretize.py b/lib/spack/spack/test/concretize.py
index 9437416b3b9..d9662747dd2 100644
--- a/lib/spack/spack/test/concretize.py
+++ b/lib/spack/spack/test/concretize.py
@@ -349,6 +349,9 @@ def test_compiler_flags_differ_identical_compilers(self):
             spec.concretize()
             assert spec.satisfies("cflags=-O2")
 
+    @pytest.mark.only_clingo(
+        "Optional compiler propagation isn't deprecated for original concretizer"
+    )
     def test_concretize_compiler_flag_propagate(self):
         spec = Spec("callpath cflags=='-g'")
         spec.concretize()
@@ -356,6 +359,16 @@ def test_concretize_compiler_flag_propagate(self):
         for dep in spec.traverse():
             assert dep.satisfies("cflags='-g'")
 
+    @pytest.mark.only_clingo(
+        "Optional compiler propagation isn't deprecated for original concretizer"
+    )
+    def test_concretize_non_root_compiler_flag_propagate(self):
+        spec = Spec("callpath ^dyninst cflags=='-g'")
+        spec.concretize()
+
+        assert spec.satisfies("^libdwarf cflags='-g'")
+        assert spec.satisfies("^libelf cflags='-g'")
+
     @pytest.mark.only_clingo(
         "Optional compiler propagation isn't deprecated for original concretizer"
     )