Firstname and lastname is not being save in s2member pro plugin

Hi,
I am using s2member pro plugin. In that I am unable to save firstname and lastname in database. in usermeta table username is being save as firstname and lastname is blank in database.

Please provide solution for the same.
Screenshot is here for your reference: http://prntscr.com/3p92eo

Thanks & Regards,
Bhavika Jadav

https://wordpress.org/plugins/s2member/