When the psychiatrist is talking to Will he clearly is holding a pen at one point, but immediately after that it is nowhere to be seen, nor any notebook to write on.
When Wolfgang is in the kitchen hiding behind the prep table, there is a rolling pin that falls off the table hit by a stray bullet. The rolling pin returns to the table when we see Wolfgang shooting from in front of the table, and disappears again as the camera angle changes.
During the final shootout between Wolfgang and Sergei, Sergei picks up a gun and fires with the slide forward. Once the gun is empty, the slide would have remained to the rear. It would have required a manual release to have it go forward.
During Riley's car wreck the vehicle flips several times. Yet later when she tries to get out all of the glass windows are still unbroken, including the windshield that was cracked by Magnus' head earlier.
During Riley's birthing scene, and later when she walks outside it is clear that she is not wearing pants but has bare upper legs. Once walking outside in the snow it switches several times between bare upper legs and pants/leggings.
When Riley's car goes off the road and flips several time apparently she gets a head wound that bleeds. The car lands and stays upside down and she is left hanging from her seat belt. Yet when she gets undone the blood from the head wound is clearly running from head to neck, not the other way around.
Throughout the series, it's quite clear a martial artist/acrobat double is performing a lot of the more demanding martial arts scenes for Sun.