diff --git a/posthog/caching/calculate_results.py b/posthog/caching/calculate_results.py
index c57c76fa26cf33..1af7b1faaa1a45 100644
--- a/posthog/caching/calculate_results.py
+++ b/posthog/caching/calculate_results.py
@@ -146,12 +146,16 @@ def calculate_for_query_based_insight(
     if isinstance(response, BaseModel):
         response = response.model_dump()
 
-    update_cached_state(  # Updating the relevant InsightCachingState
-        insight.team_id,
-        response.get("cache_key"),
-        response.get("last_refresh"),
-        result=None,  # Not caching the result here, since in HogQL this is the query runner's responsibility
-    )
+    cache_key = response.get("cache_key")
+    last_refresh = response.get("last_refresh")
+    if isinstance(cache_key, str) and isinstance(last_refresh, str):
+        update_cached_state(  # Updating the relevant InsightCachingState
+            insight.team_id,
+            cache_key,
+            last_refresh,
+            result=None,  # Not caching the result here, since in HogQL this is the query runner's responsibility
+        )
+
     return InsightResult(
         # Translating `QueryResponse` to legacy insights shape
         # The response may not be conformant with that, hence these are all `.get()`s
diff --git a/posthog/caching/insight_cache.py b/posthog/caching/insight_cache.py
index d8989a9edb515b..12fc26d8fc5cdc 100644
--- a/posthog/caching/insight_cache.py
+++ b/posthog/caching/insight_cache.py
@@ -171,7 +171,7 @@ def update_cache(caching_state_id: UUID):
 def update_cached_state(
     team_id: int,
     cache_key: str,
-    timestamp: datetime,
+    timestamp: datetime | str,
     result: Any,
     ttl: Optional[int] = None,
 ):