There are 2 possible reasons that the weekly breakdown isn't showing on the attendance tab on the student profile.
1) Sometimes if the year start date is listed incorrectly in the school details table this can cause the weekly breakdown to not display.
To check this go to Admin > Config > Core Setup > School.
If this is set to a weekend date this will need amending to the first day of the academic year.
To do this, click edit at the top of the table and enter the year start date
Then click update at the bottom of the page
2) Alternatively, this student may have been off rolled and reinstated.
To check this, go to the student's profile, and click on the 'Ancillary' tab next to the child's name.
Go down to the "School history" section to see the child's school history breakdown. Put the entry date back to what it was before the child was reinstated, and attendance will show again. To change the entry date, click on the cog in the "edit" column, input the date and click "save."