diff --git a/src/duckdb/extension/core_functions/aggregate/holistic/mode.cpp b/src/duckdb/extension/core_functions/aggregate/holistic/mode.cpp
index dc09dd32f..24f5890cf 100644
--- a/src/duckdb/extension/core_functions/aggregate/holistic/mode.cpp
+++ b/src/duckdb/extension/core_functions/aggregate/holistic/mode.cpp
@@ -234,15 +234,12 @@ struct BaseModeFunction {
 	}
 
 	template <class STATE, class OP>
-	static void Combine(const STATE &source, STATE &target, AggregateInputData &) {
+	static void Combine(const STATE &source, STATE &target, AggregateInputData &aggr_input_data) {
 		if (!source.frequency_map) {
 			return;
 		}
 		if (!target.frequency_map) {
-			// Copy - don't destroy! Otherwise windowing will break.
-			target.frequency_map = new typename STATE::Counts(*source.frequency_map);
-			target.count = source.count;
-			return;
+			target.frequency_map = TYPE_OP::CreateEmpty(aggr_input_data.allocator);
 		}
 		for (auto &val : *source.frequency_map) {
 			auto &i = (*target.frequency_map)[val.first];
diff --git a/src/duckdb/src/function/table/arrow.cpp b/src/duckdb/src/function/table/arrow.cpp
index d41f63b2c..9747d16af 100644
--- a/src/duckdb/src/function/table/arrow.cpp
+++ b/src/duckdb/src/function/table/arrow.cpp
@@ -245,10 +245,10 @@ static bool CanPushdown(const ArrowType &type) {
 	case LogicalTypeId::UBIGINT:
 	case LogicalTypeId::FLOAT:
 	case LogicalTypeId::DOUBLE:
-	case LogicalTypeId::VARCHAR:
 		return true;
+	case LogicalTypeId::VARCHAR:
 	case LogicalTypeId::BLOB:
-		// PyArrow doesn't support binary view filters yet
+		// PyArrow doesn't support binary and string view filters yet
 		return type.GetTypeInfo<ArrowStringInfo>().GetSizeType() != ArrowVariableSizeType::VIEW;
 	case LogicalTypeId::DECIMAL: {
 		switch (duck_type.InternalType()) {
diff --git a/src/duckdb/src/function/table/version/pragma_version.cpp b/src/duckdb/src/function/table/version/pragma_version.cpp
index 1e8ae5d8b..0e8af9cfa 100644
--- a/src/duckdb/src/function/table/version/pragma_version.cpp
+++ b/src/duckdb/src/function/table/version/pragma_version.cpp
@@ -1,5 +1,5 @@
 #ifndef DUCKDB_PATCH_VERSION
-#define DUCKDB_PATCH_VERSION "4-dev17"
+#define DUCKDB_PATCH_VERSION "4-dev34"
 #endif
 #ifndef DUCKDB_MINOR_VERSION
 #define DUCKDB_MINOR_VERSION 4
@@ -8,10 +8,10 @@
 #define DUCKDB_MAJOR_VERSION 1
 #endif
 #ifndef DUCKDB_VERSION
-#define DUCKDB_VERSION "v1.4.4-dev17"
+#define DUCKDB_VERSION "v1.4.4-dev34"
 #endif
 #ifndef DUCKDB_SOURCE_ID
-#define DUCKDB_SOURCE_ID "1c03ec0812"
+#define DUCKDB_SOURCE_ID "6e4e3391db"
 #endif
 #include "duckdb/function/table/system_functions.hpp"
 #include "duckdb/main/database.hpp"
diff --git a/src/duckdb/src/function/window/window_value_function.cpp b/src/duckdb/src/function/window/window_value_function.cpp
index 0258b7d6b..5eaee1423 100644
--- a/src/duckdb/src/function/window/window_value_function.cpp
+++ b/src/duckdb/src/function/window/window_value_function.cpp
@@ -468,7 +468,11 @@ void WindowFirstValueExecutor::EvaluateInternal(ExecutionContext &context, DataC
 			if (frame_width) {
 				const auto first_idx = gvstate.value_tree->SelectNth(frames, 0);
 				D_ASSERT(first_idx.second == 0);
-				cursor.CopyCell(0, first_idx.first, result, i);
+				if (first_idx.first < cursor.Count()) {
+					cursor.CopyCell(0, first_idx.first, result, i);
+				} else {
+					FlatVector::SetNull(result, i, true);
+				}
 			} else {
 				FlatVector::SetNull(result, i, true);
 			}
@@ -522,7 +526,7 @@ void WindowLastValueExecutor::EvaluateInternal(ExecutionContext &context, DataCh
 					n -= last_idx.second;
 					last_idx = gvstate.value_tree->SelectNth(frames, n);
 				}
-				if (last_idx.second) {
+				if (last_idx.second || last_idx.first >= cursor.Count()) {
 					//	No last value - give up.
 					FlatVector::SetNull(result, i, true);
 				} else {
@@ -592,7 +596,7 @@ void WindowNthValueExecutor::EvaluateInternal(ExecutionContext &context, DataChu
 
 			if (n < frame_width) {
 				const auto nth_index = gvstate.value_tree->SelectNth(frames, n - 1);
-				if (nth_index.second) {
+				if (nth_index.second || nth_index.first >= cursor.Count()) {
 					// Past end of frame
 					FlatVector::SetNull(result, i, true);
 				} else {
diff --git a/src/duckdb/src/include/duckdb/execution/merge_sort_tree.hpp b/src/duckdb/src/include/duckdb/execution/merge_sort_tree.hpp
index 8c04ecde0..4461adf38 100644
--- a/src/duckdb/src/include/duckdb/execution/merge_sort_tree.hpp
+++ b/src/duckdb/src/include/duckdb/execution/merge_sort_tree.hpp
@@ -86,6 +86,8 @@ struct MergeSortTree {
 	using RunElements = array<RunElement, F>;
 	using Games = array<RunElement, F - 1>;
 
+	static constexpr ElementType INVALID = std::numeric_limits<ElementType>::max();
+
 	struct CompareElements {
 		explicit CompareElements(const CMP &cmp) : cmp(cmp) {
 		}
@@ -122,6 +124,9 @@ struct MergeSortTree {
 	pair<idx_t, idx_t> SelectNth(const SubFrames &frames, idx_t n) const;
 
 	inline ElementType NthElement(idx_t i) const {
+		if (tree.empty() || tree.front().first.empty()) {
+			return INVALID;
+		}
 		return tree.front().first[i];
 	}
 
diff --git a/src/duckdb/src/include/duckdb/function/window/window_collection.hpp b/src/duckdb/src/include/duckdb/function/window/window_collection.hpp
index 95cf0534f..641eef78d 100644
--- a/src/duckdb/src/include/duckdb/function/window/window_collection.hpp
+++ b/src/duckdb/src/include/duckdb/function/window/window_collection.hpp
@@ -86,6 +86,10 @@ class WindowCursor {
 	WindowCursor(const WindowCollection &paged, column_t col_idx);
 	WindowCursor(const WindowCollection &paged, vector<column_t> column_ids);
 
+	//! The row count of the paged collection
+	idx_t Count() const {
+		return paged.size();
+	}
 	//! Is the scan in range?
 	inline bool RowIsVisible(idx_t row_idx) const {
 		return (row_idx < state.next_row_index && state.current_row_index <= row_idx);