Removed oe case number from CEAC Status

[Shreeya]

Hello everyone, I'm a derivative applicant of F4 category
I have my interview in few days. Next day after I got interview letter, I checked my visa status in ceac site and it showed READY along with 3 case number which is correct as we are 3 applicant, my mother, my father and me. and then after few days I randomly checked the ceac case status and there my case status is same,READY but they removed one case number . I have my interview after a week, Does anyone has any Idea why they removed one case number? Also anyone out there having similar issue ?