diff --git a/packages/material-react-table/src/components/head/MRT_TableHeadCell.tsx b/packages/material-react-table/src/components/head/MRT_TableHeadCell.tsx
index 880826e83..2fa3959ba 100644
--- a/packages/material-react-table/src/components/head/MRT_TableHeadCell.tsx
+++ b/packages/material-react-table/src/components/head/MRT_TableHeadCell.tsx
@@ -326,7 +326,7 @@ export const MRT_TableHeadCell = <TData extends MRT_RowData>({
                       column={column}
                       table={table}
                       tableHeadCellRef={{
-                        current: tableHeadCellRefs.current?.[column.id]!,
+                        current: tableHeadCellRefs.current?.[column.id] ?? null,
                       }}
                     />
                   )}
diff --git a/packages/material-react-table/src/hooks/useMRT_Effects.ts b/packages/material-react-table/src/hooks/useMRT_Effects.ts
index ce4ace2cf..6b2579c46 100644
--- a/packages/material-react-table/src/hooks/useMRT_Effects.ts
+++ b/packages/material-react-table/src/hooks/useMRT_Effects.ts
@@ -97,10 +97,10 @@ export const useMRT_Effects = <TData extends MRT_RowData>(
 
   //fix pinned row top style when density changes
   useEffect(() => {
-    if (enableRowPinning && getIsSomeRowsPinned()) {
-      setTimeout(() => {
-        rerender();
-      }, 150);
-    }
+    if (!enableRowPinning || !getIsSomeRowsPinned()) return undefined;
+    const timeoutId = setTimeout(() => {
+      rerender();
+    }, 150);
+    return () => clearTimeout(timeoutId);
   }, [density]);
 };
diff --git a/packages/material-react-table/src/hooks/useMRT_TableOptions.ts b/packages/material-react-table/src/hooks/useMRT_TableOptions.ts
index 7bee63ec6..5802a02c9 100644
--- a/packages/material-react-table/src/hooks/useMRT_TableOptions.ts
+++ b/packages/material-react-table/src/hooks/useMRT_TableOptions.ts
@@ -127,10 +127,10 @@ export const useMRT_TableOptions: <TData extends MRT_RowData>(
   mrtTheme = useMemo(() => getMRTTheme(mrtTheme, theme), [mrtTheme, theme]);
   aggregationFns = useMemo(
     () => ({ ...MRT_AggregationFns, ...aggregationFns }),
-    [],
+    [aggregationFns],
   );
-  filterFns = useMemo(() => ({ ...MRT_FilterFns, ...filterFns }), []);
-  sortingFns = useMemo(() => ({ ...MRT_SortingFns, ...sortingFns }), []);
+  filterFns = useMemo(() => ({ ...MRT_FilterFns, ...filterFns }), [filterFns]);
+  sortingFns = useMemo(() => ({ ...MRT_SortingFns, ...sortingFns }), [sortingFns]);
   defaultColumn = useMemo(
     () => ({ ...MRT_DefaultColumn, ...defaultColumn }),
     [defaultColumn],