Labelling/Tagging applicants

Labelling/Tagging applicants

Having trouble with Labelling/tagging, Seems to be very temperamental sometimes it will tag the status of an applicant and other times it will not, which can be very frustrating, after conducting a quick test to make sure it was definitely zoho and not a mistake I found that it was still having issues?, is this a common problem, is there anything simple that I am missing?, any help would be most appreciated, thank you in advance.