diff --git a/indian_paper_trading_strategy/engine/runner.py b/indian_paper_trading_strategy/engine/runner.py
index 7410309..74e1d3a 100644
--- a/indian_paper_trading_strategy/engine/runner.py
+++ b/indian_paper_trading_strategy/engine/runner.py
@@ -156,6 +156,19 @@ def _last_execution_anchor(state: dict, mode: str) -> str | None:
     return state.get("last_run") or state.get("last_sip_ts")
 
 
+def _parse_market_timestamp(value: str | None) -> datetime | None:
+    if not value:
+        return None
+    try:
+        parsed = datetime.fromisoformat(value)
+    except ValueError:
+        return None
+    market_tz = market_now().tzinfo
+    if parsed.tzinfo is None:
+        return parsed.replace(tzinfo=market_tz)
+    return parsed.astimezone(market_tz)
+
+
 def _pause_for_auth_expiry(
     user_id: str,
     run_id: str,
@@ -330,9 +343,9 @@ def _engine_loop(config, stop_event: threading.Event):
             )
 
             if last_run and not is_first_run:
-                next_run = datetime.fromisoformat(last_run) + delta
-                next_run = align_to_market_open(next_run)
-                if now < next_run:
+                parsed_last_run = _parse_market_timestamp(last_run)
+                next_run = align_to_market_open(parsed_last_run + delta) if parsed_last_run else None
+                if next_run is not None and now < next_run:
                     wait_seconds = 5 if unit == "minutes" else 60
                     log_event(
                         event="SIP_WAITING",