The legions in the founding of the Second Triumvirate are going into battle but not carrying their standards. Roman legions *always* carried their standards.
The uniforms of Octavius' guards are incorrect for the period of time.
Temples and buildings in Ancient Rome were normally painted in bright colors.
When getting back into his saddle after visiting his mother and sister, Octavian's horse is clearly fitted with stirrups. In Roman era saddles the rider had to depend on squeezing two horns in the saddle between his thighs. Stirrups were not used in and were only generally adopted in Europe. No full example of a Roman saddle remains and all those used are reconstructions at best from recovered fragments.
During the visit to Plancius' house, the water feature has modern aluminium packed tea lights floating for decoration. Metallic aluminium was first produced in the 19th century.
When Agrippa, Octavius and Maecenas are hiding in a fish cart, someone taps the side on the cart so they know when to climb out but Agrippa tells Maecenas to hurry before they're seen. As they are climbing out, two crew members can be seen holding the sides still to stop the three men falling over.