In 4.9 a picture marker symbol on a MapView rotated with the view. So we watched the mapview rotation and updated the symbol rotation accordingly to have a screen aligned image in any rotation.
In 4.10 a picture marker symbol is always displayed unrotated and aligned to the screen by default.
Before making changes to our code, i'd like to make sure that this is a feature and not a bug.
Side question for esri staff is - Could you make this behavior customizeable with a property on the symbol class?