docs: file #345 — angled input into a steep slope is fully eaten upstream of the face, UP collision normal, no slide

The user's report measured two ways: the branch probe shows the steep
face reached only 18 times with a HEALTHY applied cliff-slide (the #32
retention visibly working — lastN is the flat ground, not the face);
the flight recorder shows the actual stop is 838 uniform ticks on
nearly-flat approach terrain eating 100% of angled input with
collisionNormal straight UP and no sliding latch. Not the absorb, not
the slide family. Regression status unknown — the A/B against the
pre-campaign binary is mandated as step 1 before any theory.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/ISSUES.md

@@ -158,6 +158,43 @@ resolution.
 
 ---
 
+## #345 — Walking angled into a too-steep slope: 100% of input eaten with an UP collision normal, no slide
+
+**Status:** OPEN — HIGH (user-felt, capture-backed). Regression status UNKNOWN:
+step 1 next session is an A/B against the pre-campaign binary (d4e956b4)
+before any code is read for theories.
+**Filed:** 2026-08-08 morning, from the user's report ("I stop instead of
+sliding") + a directed 45-degree capture.
+
+**Measured** (`uphill-45deg-capture.jsonl`, 3,098 player resolves; the
+protocol held 45-deg-left / 45-deg-right / perpendicular for ~10 s each at the
+Rithwic steep face, cell 0x2F32003B):
+- Both ANGLED directions: **0.0% yield** across sustained ~30 requested
+  metres per 2 s window — the LATERAL component dies too, which retail's
+  slide-along would preserve.
+- The 838 stuck ticks are uniform: `slidingNormal=(0,0,0)` (NOT the #331
+  absorb), carried contact = nearly-flat ground `(-0.083,0.083,0.993)`
+  (~6.8 deg — not the steep face), `transient=0x3` (Contact|OnWalkable),
+  and the resolve returns `collisionNormalValid=True` with
+  **`collN=(0,0,1)` — straight UP** — position byte-identical in/out.
+- The steep face itself was reached only 18 times all session
+  (`uphill-slide-capture.log`), every one taking branch2 cliff-slide with a
+  HEALTHY constraint (`ok/last-known, apply=True`, lastN=(0,0,1) — the #32
+  retention visibly working). The stop happens UPSTREAM of the face.
+
+**What it is NOT (measured):** not the sliding-normal absorb (no latch); not
+the cliff-slide degeneracy (#32 fixed and visibly healthy); not the steep
+face's own rejection (barely reached).
+
+**Suspect space for the A/B, in order:** the step-up/step-down recursion on
+the approach terrain (an UP collision normal with zero displacement is the
+step-down-refusal shape); AD-65's away-arm snap interacting with near-flat
+normals on the approach; something older that the user only now noticed.
+DO NOT theorize past the A/B — this family has burned four
+reasoned-from-source diagnoses.
+
+---
+
 ## #344 — Mid-teleport crash: world-frame owners disagree during a long portal into a dungeon
 
 **Status:** OPEN — HIGH, user-hit during live play 2026-08-07 evening.