diff --git a/nextcloud_mcp_server/client/calendar.py b/nextcloud_mcp_server/client/calendar.py
index ec19974..dc79c84 100644
--- a/nextcloud_mcp_server/client/calendar.py
+++ b/nextcloud_mcp_server/client/calendar.py
@@ -260,7 +260,7 @@ class CalendarClient:
 
         result = []
         for event in events:
-            await event.load()
+            await event.load(only_if_unloaded=True)
             event_dict = self._parse_ical_event(event.data)
             if event_dict:
                 event_dict["href"] = str(event.url)
@@ -311,7 +311,7 @@ class CalendarClient:
 
         # Find the event by UID using caldav library
         event = await calendar.event_by_uid(event_uid)
-        await event.load()
+        await event.load(only_if_unloaded=True)
 
         # Merge updates into existing iCal data
         updated_ical = self._merge_ical_properties(event.data, event_data, event_uid)
@@ -347,7 +347,7 @@ class CalendarClient:
         calendar = self._get_calendar(calendar_name)
 
         event = await calendar.event_by_uid(event_uid)
-        await event.load()
+        await event.load(only_if_unloaded=True)
 
         event_data = self._parse_ical_event(event.data)
         if not event_data:
@@ -413,7 +413,9 @@ class CalendarClient:
 
         result = []
         for todo in todos:
-            await todo.load()
+            # Only load if data not already present from REPORT response
+            # This avoids 404 errors for virtual calendars (e.g., Deck boards)
+            await todo.load(only_if_unloaded=True)
             todo_dict = self._parse_ical_todo(todo.data)
             if todo_dict:
                 todo_dict["href"] = str(todo.url)
@@ -465,7 +467,7 @@ class CalendarClient:
         try:
             # Find the todo by UID
             todo = await calendar.todo_by_uid(todo_uid)
-            await todo.load()
+            await todo.load(only_if_unloaded=True)
 
             logger.debug(
                 f"Loaded todo {todo_uid}, current data length: {len(todo.data)}"
diff --git a/uv.lock b/uv.lock
index cb251dc..33e8edb 100644
--- a/uv.lock
+++ b/uv.lock
@@ -54,8 +54,8 @@ wheels = [
 
 [[package]]
 name = "caldav"
-version = "2.0.2.dev37+g543d3829b"
-source = { git = "https://github.com/cbcoutinho/caldav?branch=feature%2Fhttpx#543d3829b3caedadd9d3d52b91c01fd9f73cce02" }
+version = "2.0.2.dev38+g1aa2be35e"
+source = { git = "https://github.com/cbcoutinho/caldav?branch=feature%2Fhttpx#1aa2be35e94883b44efd42f1cd82d281f8f58e60" }
 dependencies = [
     { name = "httpx", extra = ["http2"] },
     { name = "icalendar" },