When the journalists are setting up their cameras in front of the warehouse, several news outlets are named. One of them is AFP (Agence France-Presse), but the company was created seven years later in 1944.
Soldiers can be seen cycling the bolts of their rifles; since cycling the bolt of a bolt-action rifle ejects shell casings, this action is only necessary after firing a round - and indicates that the rifles are, in fact, empty.
A British soldier can be seen wielding a Lee-Enfield rifle. However, the action on the Lee-Enfield is not the Lee bolt-action which the Lee-Enfield is famous for; this indicates that it may be a mock-up rifle.
Lights that get hit sometimes explode into flames. There is nothing flammable in electric lights.
The British soldiers should be equipped with the SMLE rifle; the rifles in the film are Mausers which have been converted to resemble SMLEs.
Rounds can be seen hitting people underwater. Bullets slow down enough to be unable to kill people underwater.
A Japanese soldier is seen firing a Type 11 machine gun with tracer rounds. There is no evidence that the Japanese produced tracer rounds for the 6.5mm cartridge used by the Type 11 machine gun except on an experimental basis; tracer rounds were developed by other countries post-war.
The warehouse is located on the northern bank of the Suzhou Creek; the Suzhou Creek flows eastward and joins the Yangtze River roughly one kilometer later. Therefore the Yangtze should be east of the warehouse. Yet the position of the Yangtze in the VFX shot during the plane fight scene can be seen to the west of the warehouse.