SearchOrganization strange behaviour

Hello,
this is the code I use,

    $term='4430';
    $fields="custom_fields";
    $exactMatch = true;
    $start = 0;
    $limit = 100;

and then i call SearchOrganization($term,$fields,$exactMatch,$start,$limit);
Sometimes the SearchOrganization returns 0 records even if a custom field in a Pipedrive record is populated with 4430 term
The strange behaviour is that if I recall the API a second time, most of the time one record is found.
Please note that the API call is executed during night hours and there aren’t users working in Pipedrive during this period.
How can I solve?
Best regards
Vittorio Cicognani

@Vittorio_Cicognani Do you have any knowledge on cronjob?