clear the index
drush search-api:reset-tracker freida
nohup drush search-api:index freida --batch-size=100 > /mnt/tmp/reindex.log 2>&1 &
or just
drush search-api:clear freida && nohup drush search-api:index freida --batch-size=100
where freida is your index name, freida is mine obv.