KB203166: The color for the highlighted state of a button bar selector is different in iOS mobile app 9.4.1 Update 3 compare to Update 2.

SUMMARY: In iOS mobile app 9.4.1 Update 2, when a user clicks on a button in a button bar selector, the color of the selected button will become a darker version of that button’s fill color. However, this color is always shown as gray regardless of the fill color of the button in mobile app 9.4.1 Update 3.
In Update 2:

In Update 3:

 
 
STEPS TO REPRODUCE

1. Create a document with a button bar selector.
2. Add a fill color to the selector.
3. Run the document in app 941 U2 and click on the button to observe the highlighted color is a darker version of the fill color as shown above,
4. Run the document in app 941 U3 and click on the button to observe the highlighted color is a shade of grey as shown above.

CAUSE
This is working by design. Strategy is aware of many issues where users could not distinguish the selected elements from unselected elements when the fill in color is similar to the highlighted color. Thus, the selection color logic for the button bar selector was redesigned in Update 3. In particular, the app will automatically apply the selection color based on the fill in color style. The fill in colors will be divided into two categories, light color and dark color, by the mobile client. If the fill in color is a light color, dark grey will be applied as the selection color. If the fill in color is a dark color, light grey will be applied as the selection color.
WORKAROUND
Select a fill in color for the buttons that is less contrasting to light/dark grey, which is set to be the selection color.