diff --git a/db/collection_update.go b/db/collection_update.go
index 05428a5450..047bcd5d0c 100644
--- a/db/collection_update.go
+++ b/db/collection_update.go
@@ -359,13 +359,13 @@ func (c *collection) applyMerge(
 			return errors.New("invalid field in Patch")
 		}
 
-		var err error
-		mergeCBOR[mfield], err = validateFieldSchema(mval, fd)
+		cborVal, err := validateFieldSchema(mval, fd)
 		if err != nil {
 			return err
 		}
+		mergeCBOR[mfield] = cborVal
 
-		val := client.NewCBORValue(fd.Typ, mergeCBOR[mfield])
+		val := client.NewCBORValue(fd.Typ, cborVal)
 		fieldKey, fieldExists := c.tryGetFieldKey(key, mfield)
 		if !fieldExists {
 			return client.ErrFieldNotExist
@@ -434,7 +434,7 @@ func validateFieldSchema(val *fastjson.Value, field client.FieldDescription) (in
 		return getArray(val, getString, "")
 
 	case client.FieldKind_NILLABLE_STRING_ARRAY:
-		return getArray(val, getString, nil)
+		return getNillableArray(val, getString)
 
 	case client.FieldKind_BOOL:
 		return getBool(val)
@@ -443,7 +443,7 @@ func validateFieldSchema(val *fastjson.Value, field client.FieldDescription) (in
 		return getArray(val, getBool, false)
 
 	case client.FieldKind_NILLABLE_BOOL_ARRAY:
-		return getArray(val, getBool, nil)
+		return getNillableArray(val, getBool)
 
 	case client.FieldKind_FLOAT, client.FieldKind_DECIMAL:
 		return getFloat64(val)
@@ -452,7 +452,7 @@ func validateFieldSchema(val *fastjson.Value, field client.FieldDescription) (in
 		return getArray(val, getFloat64, 0)
 
 	case client.FieldKind_NILLABLE_FLOAT_ARRAY:
-		return getArray(val, getFloat64, nil)
+		return getNillableArray(val, getFloat64)
 
 	case client.FieldKind_DATE:
 		return getDate(val)
@@ -464,7 +464,7 @@ func validateFieldSchema(val *fastjson.Value, field client.FieldDescription) (in
 		return getArray(val, getInt64, 0)
 
 	case client.FieldKind_NILLABLE_INT_ARRAY:
-		return getArray(val, getInt64, nil)
+		return getNillableArray(val, getInt64)
 
 	case client.FieldKind_OBJECT, client.FieldKind_OBJECT_ARRAY,
 		client.FieldKind_FOREIGN_OBJECT, client.FieldKind_FOREIGN_OBJECT_ARRAY:
@@ -502,8 +502,8 @@ func getDate(v *fastjson.Value) (time.Time, error) {
 func getArray[T any](
 	val *fastjson.Value,
 	typeGetter func(*fastjson.Value) (T, error),
-	zeroValue any,
-) (any, error) {
+	zeroValue T,
+) ([]T, error) {
 	if val.Type() == fastjson.TypeNull {
 		return nil, nil
 	}
@@ -513,37 +513,46 @@ func getArray[T any](
 		return nil, err
 	}
 
-	if zeroValue == nil {
-		arr := make([]*T, len(valArray))
-		for i, arrItem := range valArray {
-			if arrItem.Type() == fastjson.TypeNull {
-				arr[i] = nil
-				continue
-			}
-			v, err := typeGetter(arrItem)
-			if err != nil {
-				return nil, err
-			}
-			arr[i] = &v
+	arr := make([]T, len(valArray))
+	for i, arrItem := range valArray {
+		if arrItem.Type() == fastjson.TypeNull {
+			arr[i] = zeroValue
+			continue
+		}
+		arr[i], err = typeGetter(arrItem)
+		if err != nil {
+			return nil, err
 		}
-		return arr, nil
 	}
 
-	arr := make([]T, len(valArray))
+	return arr, nil
+}
+
+func getNillableArray[T any](
+	val *fastjson.Value,
+	typeGetter func(*fastjson.Value) (T, error),
+) ([]*T, error) {
+	if val.Type() == fastjson.TypeNull {
+		return nil, nil
+	}
+
+	valArray, err := val.Array()
+	if err != nil {
+		return nil, err
+	}
+
+	arr := make([]*T, len(valArray))
 	for i, arrItem := range valArray {
 		if arrItem.Type() == fastjson.TypeNull {
-			var ok bool
-			arr[i], ok = zeroValue.(T)
-			if !ok {
-				return nil, errors.New("zeroValue should be of the same type as the array items type")
-			}
 			continue
 		}
-		arr[i], err = typeGetter(arrItem)
+		v, err := typeGetter(arrItem)
 		if err != nil {
 			return nil, err
 		}
+		arr[i] = &v
 	}
+
 	return arr, nil
 }