diff --git a/docs/ISSUES.md b/docs/ISSUES.md
index 2a7cfe43..16f94ce7 100644
--- a/docs/ISSUES.md
+++ b/docs/ISSUES.md
@@ -42,18 +42,68 @@ The human Setup `0x02000001` authors `StepUpHeight = 0.600` and
 `StepDownHeight = 1.500`. The live `[support]` probe lines show the player
 resolving with `stepUp=0.400 stepDown=0.400`.
 
-### What is NOT yet established
+### ANSWERED 2026-08-06 — retail DOES read the authored field, so this is real
+
+The gating question is closed. `CTransition::step_up` @0x0050b610
+(`acclient_2013_pseudo_c.txt:273109-273117`):
+
+```
+0050b655   float step_up_height = 0.0399999991f;      // fallback
+0050b661   if ((this->object_info.state & 2) != 0) {  // <- the gate
+0050b665       OBJECTINFO::get_walkable_z(this);
+0050b671       step_up_height = this->object_info.step_up_height;   // authored
+           }
+0050b6ba   CTransition::step_down(this, step_up_height, arg2)
+```
+
+`step_down` has the same shape at `0x0050b852` (default `0.04`, conditional
+substitution) and reads the authored value unconditionally at `0x0050c232`,
+where it is then halved against the sphere radius if it exceeds a diameter.
+
+**Two facts fall out of this, and the second is the more useful one.**
+
+**(1) The fallback is `0.04`, not `0.4`.** Our value matches neither retail's
+fallback nor the authored `0.600`/`1.500`. It is an order of magnitude above
+retail's fallback and well below the authored value.
+
+**(2) `state & 2` is `OnWalkable`** in our own `ObjectInfoState`. So retail
+applies the authored step height ONLY while standing on walkable ground, and
+drops to `0.04` otherwise. **We already port that gate correctly** —
+`Transition.DoStepUp` (`TransitionTypes.cs` ~5836) is a faithful copy,
+including `stepDownHeight = oi.StepUpHeight`, which reads oddly but is exactly
+what retail passes. **The gate is not the defect. Only the VALUE fed into it
+is.**
+
+### Where the 0.4 comes from — mapped, with one hop unproven
+
+- `PlayerMovementController._stepUpHeight` / `_stepDownHeight` are
+  **initialised to `0.4f`** (`PlayerMovementController.cs:159-160`).
+- The `StepUpHeight` property's own doc comment says the authoritative source
+  is the player's `Setup.StepUpHeight`, set by
+  **`PlayerModeController.ApplyStepHeights`**. **That method does not exist
+  anywhere in the tree** — the identifier appears exactly once, inside that
+  comment. Either the wiring was removed and the comment survived, or it never
+  landed.
+- **Remotes and live entities are NOT affected.** They get Setup-derived
+  values: `LiveEntityMotionRuntimeController.cs:321`
+  (`setup.StepUpHeight * scale`, falling back to `0.4f`) and
+  `RuntimeSetPositionMoverPreparation.cs:180`. The local player is the odd one
+  out — which is the population that matters, since it is what the user feels.
+
+**NOT ESTABLISHED, and must be before any fix.** There IS one real writer:
+`RuntimeLocalPlayerPhysicsPublicationState.cs:215-216` assigns from
+`command.Physics.StepUpHeight`, and that command is built by
+`RuntimeSetPositionMoverPreparation` — which *does* compute the Setup-derived
+value. So the plumbing exists. Whether it runs for the local player, or runs
+and is then overwritten, is unproven; the live probe reading `0.400` says the
+controller held its default at that moment, not why. **Print the controller's
+two values at world entry and at the first resolve before changing anything.**
+A fix that sets the field without knowing which path won will be a coin flip.
+
+### Remaining open question
 
-- Whether the authored Setup values are what retail feeds `CPhysicsObj`, or
-  whether retail also substitutes constants at this seam. **Grep
-  `named-retail` for `get_stepup_height` / `get_stepdown_height` and their
-  callers before touching anything** — the authored DAT field being ignored is
-  only a defect if retail reads it.
-- Where the 0.400 comes from: a hardcoded default, a stance/posture-dependent
-  value, or a value that never got wired from the Setup.
 - Whether it has any observable consequence. Do not open this by reasoning
   from the source; the #337 lineage already burned two diagnoses that way.
-
 ### Related
 
 Sits next to #32 (local-player cliff edge-slide), which has its own research