The flag in the office is on the staff upside down.
The railroad station shown as "Toronto" station, while appropriate for the era, is a small town, rural station not one suitable for a burgeoning metropolis like 19th Century Toronto.
Microwave burst at the end moves slow enough for the camera to follow the action. But microwaves are light and move at the speed of light.
The cartridges from a revolver are magnetically attracted to Sally Pendricks' purse. Since both casing and bullets are made of non-magnetic metal, this should not happen.
When James Pendrick removes the bullets from his gun and places them on the desk a dimple can clearly be seen in the primer of one of the cartridges. This means that the round has been fired but the bullet is still in place. It is likely that the producers, for safety reasons, chose to use spent cartridges as props, pressing the bullet into the end for authenticity.
In year 2, "The Green Muse", William and Julia have their first intimate moment. Julia states that they should not proceed without protection, for what appears to be fear of pregnancy. But now Julia states that she is sterile from her previous abortion.