日期没有存储在PHP中的.xlsx工作表的数据库中

I have a page to save an excel sheet records to the database. The records are being stored same way as they are provided in excel sheet other than "date of birth" column. The "Date of Birth" column saves only for the second record being uploaded from excel sheet. I had been searching a lot on this but not found the exact reason for it.I have a page to save an excel sheet records to