diff --git a/port/scripts/boot.gd b/port/scripts/boot.gd
index e111acaa..d10d4dc2 100644
--- a/port/scripts/boot.gd
+++ b/port/scripts/boot.gd
@@ -995,8 +995,20 @@ func _unhandled_input(event: InputEvent) -> void:
 	if overlay != null and event.is_action_pressed("ui_accept"):
 		var snap_to := overlay.settle_time()
 		if snap_to > 0.0 and view.time_units < snap_to:
-			print("  (A) snaps the title: shared clock %.1f -> %.1f" % [view.time_units, snap_to])
+			print("  (A) snaps the title: shared clock %.1f -> %.1f, leaves restart at 0"
+				% [view.time_units, snap_to])
 			view.time_units = snap_to
+			# 🔴 THE LEAVES RESTART AT THEIR OWN t=0; the snap is not only a clock
+			# advance. MEASURED: at the snap frame both sweeps enter at their
+			# DECLARED OPENING alphas -- `pteff03` at 255, `pteff03a` at 0 rising
+			# 1,2,3,4,6,11,17 from x=1721
+			# (`docs/re/f5-verified-with-full-quad-reader.md`).
+			#
+			# Advancing the shared clock alone would leave the leaf phase where it
+			# was, so the sweeps would sit mid-travel at the right clock value and
+			# the wrong position -- a defect visible only in a film, and one this
+			# implementation had until this line.
+			view.leaf_start_units = snap_to
 			view.queue_redraw()
 			_overlay_process(0.0)
 			return