Stud Not Missing
On 2018-2019 Toyota Camry and 2019 Avalon vehicles equipped with a 2GR-FKS engine, technicians may observe that the bank 1 (rear) exhaust manifold may be missing a stud and nut.
The repair manual shows that, as per design intent, the exhaust manifold is NOT missing this stud and nut. Even if it certainly looks like a stud and nut are missing, Toyota states that you should NOT attempt to add a stud and nut to the upper left manifold flange hole location.
Even though the flange features five holes, only four are installed intentionally.