diff --git a/backend/app/routers/events.py b/backend/app/routers/events.py
index 7b0b501..6b2b022 100644
--- a/backend/app/routers/events.py
+++ b/backend/app/routers/events.py
@@ -401,6 +401,13 @@ async def delete_event(
                     CalendarEvent.original_start >= this_original_start,
                 )
             )
+            # Ensure the target event itself is deleted (edge case: original_start fallback mismatch)
+            existing = await db.execute(
+                select(CalendarEvent).where(CalendarEvent.id == event_id)
+            )
+            target = existing.scalar_one_or_none()
+            if target:
+                await db.delete(target)
         else:
             # This event IS the parent — delete it and all children (CASCADE handles children)
             await db.delete(event)
diff --git a/backend/app/routers/locations.py b/backend/app/routers/locations.py
index d21f641..644769b 100644
--- a/backend/app/routers/locations.py
+++ b/backend/app/routers/locations.py
@@ -2,6 +2,7 @@ from fastapi import APIRouter, Depends, HTTPException, Query
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select, or_
 from typing import Optional, List
+import asyncio
 import json
 import urllib.request
 import urllib.parse
@@ -51,28 +52,29 @@ async def search_locations(
             )
         )
 
-    # Nominatim proxy search
-    try:
+    # Nominatim proxy search (run in thread executor to avoid blocking event loop)
+    def _fetch_nominatim() -> list:
         encoded_q = urllib.parse.quote(q)
         url = f"https://nominatim.openstreetmap.org/search?q={encoded_q}&format=json&limit=5"
-        req = urllib.request.Request(
-            url,
-            headers={"User-Agent": "UMBRA-LifeManager/1.0"},
-        )
+        req = urllib.request.Request(url, headers={"User-Agent": "UMBRA-LifeManager/1.0"})
         with urllib.request.urlopen(req, timeout=5) as resp:
-            osm_data = json.loads(resp.read().decode())
-            for item in osm_data:
-                display_name = item.get("display_name", "")
-                name_parts = display_name.split(",", 1)
-                name = name_parts[0].strip()
-                address = name_parts[1].strip() if len(name_parts) > 1 else display_name
-                results.append(
-                    LocationSearchResult(
-                        source="nominatim",
-                        name=name,
-                        address=address,
-                    )
+            return json.loads(resp.read().decode())
+
+    try:
+        loop = asyncio.get_running_loop()
+        osm_data = await loop.run_in_executor(None, _fetch_nominatim)
+        for item in osm_data:
+            display_name = item.get("display_name", "")
+            name_parts = display_name.split(",", 1)
+            name = name_parts[0].strip()
+            address = name_parts[1].strip() if len(name_parts) > 1 else display_name
+            results.append(
+                LocationSearchResult(
+                    source="nominatim",
+                    name=name,
+                    address=address,
                 )
+            )
     except Exception as e:
         logger.warning(f"Nominatim search failed: {e}")
 
diff --git a/backend/app/schemas/calendar_event.py b/backend/app/schemas/calendar_event.py
index c219539..54e40ff 100644
--- a/backend/app/schemas/calendar_event.py
+++ b/backend/app/schemas/calendar_event.py
@@ -1,6 +1,6 @@
 import json as _json
 
-from pydantic import BaseModel, ConfigDict, field_validator
+from pydantic import BaseModel, ConfigDict, Field, field_validator
 from datetime import datetime
 from typing import Literal, Optional
 
@@ -9,13 +9,13 @@ class RecurrenceRule(BaseModel):
     """Structured recurrence rule — serialized to/from JSON string in the DB column."""
     type: Literal["every_n_days", "weekly", "monthly_nth_weekday", "monthly_date"]
     # every_n_days
-    interval: Optional[int] = None
+    interval: Optional[int] = Field(None, ge=1, le=365)
     # weekly / monthly_nth_weekday
-    weekday: Optional[int] = None  # 0=Mon … 6=Sun
+    weekday: Optional[int] = Field(None, ge=0, le=6)  # 0=Mon … 6=Sun
     # monthly_nth_weekday
-    week: Optional[int] = None     # 1-4
+    week: Optional[int] = Field(None, ge=1, le=4)
     # monthly_date
-    day: Optional[int] = None      # 1-31
+    day: Optional[int] = Field(None, ge=1, le=31)
 
 
 def _coerce_recurrence_rule(v):
diff --git a/frontend/src/components/calendar/CalendarPage.tsx b/frontend/src/components/calendar/CalendarPage.tsx
index dd0f0a4..a96371f 100644
--- a/frontend/src/components/calendar/CalendarPage.tsx
+++ b/frontend/src/components/calendar/CalendarPage.tsx
@@ -192,6 +192,12 @@ export default function CalendarPage() {
       info.revert();
       return;
     }
+    // Prevent drag-drop on recurring events — user must use scope dialog via click
+    if (info.event.extendedProps.is_recurring || info.event.extendedProps.parent_event_id) {
+      info.revert();
+      toast.info('Click the event to edit recurring events');
+      return;
+    }
     const id = parseInt(info.event.id);
     const start = info.event.allDay
       ? info.event.startStr
@@ -211,6 +217,12 @@ export default function CalendarPage() {
       info.revert();
       return;
     }
+    // Prevent resize on recurring events — user must use scope dialog via click
+    if (info.event.extendedProps.is_recurring || info.event.extendedProps.parent_event_id) {
+      info.revert();
+      toast.info('Click the event to edit recurring events');
+      return;
+    }
     const id = parseInt(info.event.id);
     const start = info.event.allDay
       ? info.event.startStr
diff --git a/frontend/src/components/ui/location-picker.tsx b/frontend/src/components/ui/location-picker.tsx
index 463687f..073e17a 100644
--- a/frontend/src/components/ui/location-picker.tsx
+++ b/frontend/src/components/ui/location-picker.tsx
@@ -23,6 +23,7 @@ export default function LocationPicker({ value, onChange, onSelect, placeholder
   const [isOpen, setIsOpen] = useState(false);
   const [isLoading, setIsLoading] = useState(false);
   const debounceRef = useRef<ReturnType<typeof setTimeout>>();
+  const requestIdRef = useRef(0);
   const containerRef = useRef<HTMLDivElement>(null);
 
   useEffect(() => {
@@ -35,17 +36,22 @@ export default function LocationPicker({ value, onChange, onSelect, placeholder
     }
 
     debounceRef.current = setTimeout(async () => {
+      const thisRequestId = ++requestIdRef.current;
       setIsLoading(true);
       try {
         const { data } = await api.get<LocationSearchResult[]>('/locations/search', {
           params: { q: value },
         });
+        if (thisRequestId !== requestIdRef.current) return; // stale response
         setResults(data);
         setIsOpen(data.length > 0);
       } catch {
+        if (thisRequestId !== requestIdRef.current) return;
         setResults([]);
       } finally {
-        setIsLoading(false);
+        if (thisRequestId === requestIdRef.current) {
+          setIsLoading(false);
+        }
       }
     }, 300);
 
diff --git a/frontend/src/components/ui/sheet.tsx b/frontend/src/components/ui/sheet.tsx
index f6e3fa3..65cebc9 100644
--- a/frontend/src/components/ui/sheet.tsx
+++ b/frontend/src/components/ui/sheet.tsx
@@ -28,6 +28,13 @@ const Sheet: React.FC<SheetProps> = ({ open, onOpenChange, children }) => {
     }
   }, [open]);
 
+  // Safety cleanup: restore overflow if component unmounts while open
+  React.useEffect(() => {
+    return () => {
+      document.body.style.overflow = '';
+    };
+  }, []);
+
   React.useEffect(() => {
     const handleEscape = (e: KeyboardEvent) => {
       if (e.key === 'Escape') onOpenChange(false);
@@ -50,6 +57,8 @@ const Sheet: React.FC<SheetProps> = ({ open, onOpenChange, children }) => {
         onClick={() => onOpenChange(false)}
       />
       <div
+        role="dialog"
+        aria-modal="true"
         className={cn(
           'fixed right-0 top-0 h-full w-full max-w-[540px] transition-transform duration-350',
           visible ? 'translate-x-0' : 'translate-x-full'