Fix yellow cast at consecutive transitions and maps stacking

Transition center was placed at cumulative_latent_frames - overlap//2,
inside scene 1's territory. Since overlap frames are pinned (mask=0)
the latent blend is a no-op, so the actual content seam is at
cumulative_latent_frames exactly. Centering there puts the seam at
peak black, hiding any decode artifacts and giving a clean post-processed
fade-to-black feel on each side.

Maps stacking: _capture_finalizer merged new captures with the existing
temp file, including leftovers from previous ComfyUI runs. Each "loved it"
cycle blessed maps that had been tainted by the previous round's injection,
compounding color bias indefinitely. Clear the temp file at build_enhancements
start so each generation captures clean.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ltx_enhancements.py

@@ -566,6 +566,18 @@ def build_enhancements(model, rating_profile, temporal_style, refinement_key, re
     }
 
     # --- Technique 5: injection data ---
+    # Clear the temp maps file so this generation's capture starts fresh.
+    # Without this, maps from previous runs merge in and compound across
+    # sessions — each "loved it" cycle injects tainted states from the
+    # previous round, producing progressively worse color bias.
+    if refinement_key:
+        temp_path = _temp_maps_path(refinement_key)
+        try:
+            if os.path.exists(temp_path):
+                os.remove(temp_path)
+        except Exception:
+            pass
+
     has_i2v = reference_latent is not None and _has_i2v_reference(reference_latent)
     if has_i2v:
         # i2v latent: extract reference maps on first generation step (real conditioning available).

samplers.py

@@ -1467,7 +1467,10 @@ class FunPackLTXAVSceneChainSampler:
                 # Record boundary (center of the overlap region) before blending
                 effect = self._scene_transition_effect(scene_cond)
                 if effect and transition_duration > 0:
-                    boundary_latent = max(0, cumulative_latent_frames - video_overlap // 2)
+                    # Seam is at cumulative_latent_frames: overlap frames are pinned
+                    # (mask=0) so the latent blend is a no-op — the actual content
+                    # boundary is exactly here, not offset by overlap//2.
+                    boundary_latent = cumulative_latent_frames
                     boundary_pixel = int((boundary_latent - 1) * time_scale + 1) if time_scale > 1 else boundary_latent
                     blend_half_latent = max(1, video_overlap // 2)
                     blend_half_pixels = blend_half_latent * time_scale