This conversation has been merged. Please reference the main conversation: Photoshop CC 2019: Drop shadow changes distance from the object depending on the zoom level and I get green or red boxes over the image
Having opened an existing PSD file, my default drop shadow effect appeared very different. I manually adjusted the effects to get the desired result.
However, when I saved a JPG copy, the JPG is again very different to the desired result.
Furthermore, the JPG preview thumbnail is displaying the effect completely differently.