diff --git a/crudkit/core/service.py b/crudkit/core/service.py
index 753d90f..7f4bbcf 100644
--- a/crudkit/core/service.py
+++ b/crudkit/core/service.py
@@ -76,6 +76,20 @@ def _collect_tables_from_filters(filters) -> set:
         visit(f)
     return seen
 
+def _selectable_keys(sel) -> set[str]:
+    """
+    Return a set of stable string keys for a selectable/alias and its base,
+    so we can match when when different alias objects are used.
+    """
+    keys: set[str] = set()
+    cur = sel
+    while cur is not None:
+        k = getattr(cur, "key", None) or getattr(cur, "name", None)
+        if isinstance(k, str) and k:
+            keys.add(k)
+        cur = getattr(cur, "element", None)
+    return keys
+
 def _unwrap_ob(ob):
     elem = getattr(ob, "element", None)
     col = elem if elem is not None else ob
@@ -244,6 +258,7 @@ class CRUDService(Generic[T]):
         collection_field_names: Any
         join_paths: Any
         filter_tables: Any
+        filter_table_keys: Any
         req_fields: Any
         proj_opts: Any
 
@@ -259,12 +274,19 @@ class CRUDService(Generic[T]):
         join_paths = tuple(spec.get_join_paths())
         filter_tables = _collect_tables_from_filters(filters)
         _, proj_opts = compile_projection(self.model, req_fields) if req_fields else ([], [])
+        # Precompute a string-key set for quick/stable membership tests
+        fkeys: set[str] = set()
+        for t in filter_tables:
+            try:
+                fkeys |= _selectable_keys(t)
+            except Exception:
+                pass
 
         return self._Plan(
             spec=spec, filters=filters, order_by=order_by, limit=limit, offset=offset,
             root_fields=root_fields, rel_field_names=rel_field_names,
             root_field_names=root_field_names, collection_field_names=collection_field_names,
-            join_paths=join_paths, filter_tables=filter_tables,
+            join_paths=join_paths, filter_tables=filter_tables, filter_table_keys=fkeys,
             req_fields=req_fields, proj_opts=proj_opts
         )
 
@@ -278,16 +300,20 @@ class CRUDService(Generic[T]):
             if base_alias is not root_alias:
                 continue
             prop = getattr(rel_attr, "property", None)
+            if log.isEnabledFor(logging.DEBUG):
+                try:
+                    sel = getattr(target_alias, "selectable", None)
+                    sel_key = getattr(sel, "key", None) or getattr(sel, "name", None)
+                    log.debug(
+                        "FIRST-HOP plan: rel=%s collection=%s selectable=%s filter_keys=%s",
+                        rel_attr.key, getattr(prop, "uselist", False), sel_key, getattr(plan, "filter_table_keys", set())
+                    )
+                except Exception:
+                    pass
             is_collection = bool(getattr(prop, "uselist", False))
 
-            sel = getattr(target_alias, "selectable", None)
-            sel_elem = getattr(sel, "element", None)
-            base_sel = sel_elem if sel_elem is not None else sel
-
-            needed_for_filter = (sel in plan.filter_tables) or (base_sel in plan.filter_tables)
-
-            if needed_for_filter and not is_collection:
-                query = query.join(rel_attr, isouter=True)
+            if not is_collection:
+                query = query.join(target_alias, rel_attr.of_type(target_alias), isouter=True)
             else:
                 opt = selectinload(rel_attr)
                 if is_collection:
@@ -407,7 +433,7 @@ class CRUDService(Generic[T]):
             base = self._apply_not_deleted(base, root_alias, params)
             for _b, rel_attr, target_alias in plan.join_paths:
                 if not bool(getattr(getattr(rel_attr, "property", None), "uselist", False)):
-                    base = base.join(rel_attr, isouter=True)
+                    base = base.join(target_alias, rel_attr.of_type(target_alias), isouter=True)
             if plan.filters:
                 base = base.filter(*plan.filters)
             total = session.query(func.count()).select_from(