Different marks

Hello

I'm having issues with marks when children do the worksheets at home. They get a mark and I see a different one or even a 0.

https://www.liveworksheets.com/student-workbook/result/2778154/worksheet/dTF2Kog8qn

In this one, she gets an 8 and I see a 0.

Any ideas why this is happening? I've been using this website for 3 years but after the update, there are many issues going on.

Thanks!