At 38:46 and 39:30, Mary is driving the wagon quickly. It is obviously a stand in as the hair is very different from Mary's hair.
When Stanley stops breathing at 15:05, you can still see his jugular vein pulsing.
As Dr. Baker is closing up his office (after Ms. Oleson's visit) to go to the Novak farm, a crew or cast member is clearly reflected in the light panel next to the door. Then later in the episode as Dr. Baker is leaving his office once the new doctor has moved in, Mary's bonnet is reflected in the panel. She was just off camera waiting to ride in for the next scene. For a brief moment it looks like she is leaning forward to pick up the reins on the horses.
Boom mic shadow is visible moving in the doctor office.
Retirement or not, Dr Baker would never have left his framed medical school diploma behind in the office he was turning over to Dr Logan.