fix: ignore pre-history prediction acknowledgements

Game/scripts/local_prediction_history.gd

@@ -73,6 +73,7 @@ const RING_SIZE := 128
 var _ring_seq: PackedInt32Array = PackedInt32Array()
 var _ring_entry: Array = []
 var _has_recorded := false
+var _first_recorded_seq := -1
 
 var newest_recorded_seq := -1
 var last_acknowledged_seq := 0
@@ -94,6 +95,7 @@ func begin_epoch() -> void:
 		_ring_seq[i] = -1
 		_ring_entry[i] = null
 	_has_recorded = false
+	_first_recorded_seq = -1
 	newest_recorded_seq = -1
 	last_acknowledged_seq = 0
 	resync_required = false
@@ -106,6 +108,8 @@ func begin_epoch() -> void:
 func record(seq: int, action: ShipAction, state: NetBodyState, contact_window: bool = false) -> bool:
 	var overflowed_now := false
 	if not _has_recorded or seq > newest_recorded_seq:
+		if not _has_recorded:
+			_first_recorded_seq = seq
 		if seq - last_acknowledged_seq > RING_SIZE:
 			# Only the LEADING edge of an episode counts: resync_required is
 			# still true for every subsequent tick of the same stall, and
@@ -140,6 +144,8 @@ func record(seq: int, action: ShipAction, state: NetBodyState, contact_window: b
 func record_unsimulated(seq: int, action: ShipAction) -> bool:
 	var overflowed_now := false
 	if not _has_recorded or seq > newest_recorded_seq:
+		if not _has_recorded:
+			_first_recorded_seq = seq
 		if seq - last_acknowledged_seq > RING_SIZE:
 			overflowed_now = not resync_required
 			resync_required = true
@@ -289,6 +295,11 @@ func compare_authoritative(seq: int, authoritative: NetBodyState) -> Dictionary:
 
 
 func _missing_status(seq: int) -> String:
+	# The server starts its acknowledgement clock at sequence 0, while the
+	# first local post-step prediction is normally sequence 1. This is a normal
+	# startup boundary, not a lost ring entry and must not trigger a hard snap.
+	if not _has_recorded or seq < _first_recorded_seq:
+		return "warmup_not_recorded"
 	if _has_recorded and seq <= newest_recorded_seq - RING_SIZE:
 		return "missing_evicted"
 	return "missing_not_recorded"

Game/scripts/net_ship_predictor.gd

@@ -44,6 +44,11 @@ static func decide(comparison: Dictionary, local_frozen: bool, reset_changed: bo
 	# normally against real data.
 	if comparison.get("status", "") == "unsimulated_gap":
 		return {"mode": "skip", "reason": "unsimulated_gap"}
+	if comparison.get("status", "") == "warmup_not_recorded":
+		# Sequence acknowledgements that predate the first local post-step state
+		# are expected during startup. The initial snapshot already placed the
+		# body, so there is no correction to apply and no resync to arm.
+		return {"mode": "skip", "reason": "warmup_not_recorded"}
 	if comparison.get("status", "missing_not_recorded") != "matched":
 		return {"mode": "hard", "reason": comparison.get("status", "missing")}
 	if authoritative == null or authoritative.frozen != local_frozen: