Timesheets don't show planned tasks

Hi,

I'm using Project 2016 with projects on-line. I am trying to resolve a very frustrating issue for one of my users which I just can explain. The issue is:

The user has a task that runs from 16/03/20 to 17/04/20. The user can see the planned work assignments in MS Project with 6 hours per day for that period. They are the task owner and they are committed to the assignment.

In projects on-line I can see this under the resource view (resource assignments and capacity planning). The user can see the assignment from 16th to 20th in their timesheet but not for the week 23rd to 27th which is blank. There is no non-working period listed under that resource for that time either or the project.

I'm baffled as to why this is missing from just that week when the rest of the weeks show correctly in the timesheet. I would appreciate some advice on what I might have missed or could try. 

Many thanks