anybody tried added search filters to an existing saved search using filterExpression? Code below does not work

var filtersExpression = recSs.filterExpression;
                filtersExpression = filtersExpression.concat(aFilters);

                log.debug('append filters', filtersExpression);

                recSs.filtersExpression = filtersExpression;

Confirmed from the logs that the new filters are added in the

filtersExpression

variable. But when I get the filters after the

recSs.filtersExpression = filtersExpression;

, it is still the original filters.