I have installed module Purchase, Expense, and Accounting. And then, I have one user who have access right as Purchase User and Expense Team Approver.

Because of this user access as Expense Team Approver, it means he/she can access All Expense Report related to him. But unfortunately when he/she try to open an Already Posted Expense Report, Odoo gave error message related to access rule error for record rule Purchase User Account Move

When i tried to read the record rule, it said that Purchase User can only access account.move / Journal Entry which has a type in in_invoice and in_refund. It means that the user can only access Bills Journal Entry. 

Journal Entry that created by Expense Report menu is not a Bill Journal Entry, thats why he/she could not accessed this document

It means that Expense Team Approver cannot have the same access as Purchase User. And this is a odoo basic module bugs.