User is trying to write a check for an employee and is prompted to import the reimbursable expenses of that employee. After importing the expenses, the user is unable to edit the check and cannot make changes to the entries on the grid.
This is the expected behavior in Core. As of now, it does not allow you to make any changes to the check after you import the reimbursable expenses. But if you save the check and then try to make changes to it, Core allows that and you can add or remove items from the grid. The changes you make to the imported expenses also reflect on the Expense Entries screen. Check the Core Help for more on writing checks for reimbursable expenses.