Always reproduced:

```
milovidov-desktop :) create table table_map (a Map(String, String), b String) engine = MergeTree() order by a;

CREATE TABLE table_map
(
    `a` Map(String, String),
    `b` String
)
ENGINE = MergeTree
ORDER BY a

Query id: 8f8120c1-c165-452a-815f-2bcae3957e2a

Ok.

0 rows in set. Elapsed: 0.002 sec. 

milovidov-desktop :) SELECT b FROM table_map WHERE a = map('name', NULL, '', NULL)

SELECT b
FROM table_map
WHERE a = {'name', NULL, '', NULL}
```
else if (source_is_nullable)
        {
            
            return [wrapper, skip_not_null_check]
                (ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, const ColumnNullable *, size_t input_rows_count) -> ColumnPtr
            {
                auto tmp_args = createBlockWithNestedColumns(arguments);
                auto nested_type = removeNullable(result_type);
                
                
                
                if (!skip_not_null_check)
                {
                    const auto & col = arguments[0].column;
                    const auto & nullable_col = assert_cast<const ColumnNullable &>(*col);
                    const auto & null_map = nullable_col.getNullMapData();
                    if (!memoryIsZero(null_map.data(), null_map.size()))
                        throw Exception{"Cannot convert NULL value to non-Nullable type",
                                        ErrorCodes::CANNOT_INSERT_NULL_IN_ORDINARY_COLUMN};
                }
                const ColumnNullable * nullable_source = typeid_cast<const ColumnNullable *>(arguments.front().column.get());
                return wrapper(tmp_args, nested_type, nullable_source, input_rows_count);
            };
        }
        else
            return wrapper;
    }
    
    
    WrapperType prepareImpl(const DataTypePtr & from_type, const DataTypePtr & to_type, bool requested_result_is_nullable) const