diff --git a/src/AcDream.Core/Physics/TransitionTypes.cs b/src/AcDream.Core/Physics/TransitionTypes.cs
index 6f73771..cc6944a 100644
--- a/src/AcDream.Core/Physics/TransitionTypes.cs
+++ b/src/AcDream.Core/Physics/TransitionTypes.cs
@@ -630,9 +630,17 @@ public sealed class Transition
 
                 float radsum = sp.GlobalSphere[0].Radius * 2f;
 
+                // L.2.3h (2026-04-29): pass runPlacement=false. This
+                // branch's job is to maintain ground contact during normal
+                // movement (e.g., walking over small bumps or near walls).
+                // The Placement check inside DoStepDown is too strict for
+                // this use — minor wall overlap from a prior wall-slide
+                // would fail Placement and trigger the L.2.3e edge-block,
+                // leaving the player stuck near walls. DoStepUp still runs
+                // Placement for the step-UP-through-walls protection.
                 if (radsum >= stepDownHeight)
                 {
-                    if (DoStepDown(stepDownHeight, zVal, engine))
+                    if (DoStepDown(stepDownHeight, zVal, engine, runPlacement: false))
                     {
                         sp.WalkableValid = false;
                         return TransitionState.OK;
@@ -641,8 +649,8 @@ public sealed class Transition
                 else
                 {
                     stepDownHeight *= 0.5f;
-                    if (DoStepDown(stepDownHeight, zVal, engine)
-                     || DoStepDown(stepDownHeight, zVal, engine))
+                    if (DoStepDown(stepDownHeight, zVal, engine, runPlacement: false)
+                     || DoStepDown(stepDownHeight, zVal, engine, runPlacement: false))
                     {
                         sp.WalkableValid = false;
                         return TransitionState.OK;
@@ -1314,7 +1322,8 @@ public sealed class Transition
     /// Ported from pseudocode section 5 (StepDown).
     /// ACE: Transition.StepDown(float stepDownHeight, float zVal).
     /// </summary>
-    private bool DoStepDown(float stepDownHeight, float walkableZ, PhysicsEngine engine)
+    private bool DoStepDown(float stepDownHeight, float walkableZ, PhysicsEngine engine,
+                             bool runPlacement = true)
     {
         var sp = SpherePath;
 
@@ -1348,6 +1357,22 @@ public sealed class Transition
             && CollisionInfo.ContactPlaneValid
             && CollisionInfo.ContactPlane.Normal.Z >= walkableZ)
         {
+            // L.2.3h (2026-04-29): Placement validation is for the
+            // DoStepUp use case (prevents climbing through walls by
+            // stepping up onto ground beyond a tall wall). For the
+            // "maintain contact during normal movement" use case (called
+            // from TransitionalInsert's contact-recovery branch), the
+            // Placement check is over-strict — slight wall overlap from
+            // a prior wall-slide makes Placement reject, then the caller
+            // returns Collided (L.2.3e) and the player gets stuck near
+            // walls without ever touching them.
+            //
+            // ACE Transition.cs:731-741 runs Placement here unconditionally,
+            // but ACE's pre-step-down state is cleaner — we have residual
+            // wall-slide artifacts that make Placement misfire.
+            if (!runPlacement)
+                return true;
+
             // Placement validation: can we actually stand here?
             var savedInsert = sp.InsertType;
             sp.InsertType   = InsertType.Placement;