Enabling Use Pawn Control Rotation on a SpringArm component does not set the rotation values to zero, and subsequent rotation is not allowed after the setting is disabled

Enabling Use Pawn Control Rotation on a SpringArm component does not set the rotation values to zero. Subsequently disabling Pawn Use Control Rotation make rotation of the component impossible until it has been completely zeroed out, after which it behaves as expected.

Reproduced in 4.9.2, 4.10.1, and Main (CL# 2813452, 4.12).

1. Open a new blank project
2. Create a new Character blueprint
3. Add a Spring Arm component
4. Set the Rotation to 0, -45, 0
5. Enable Use Pawn Control Rotation
6. Note the change in rotation, but no change in the Transform values in the Details tab
7. Disable Use Pawn Control Rotation
8. Rotate the Spring Arm component, either with Detail panel or with rotate widget

Result:
The values in the details panel do not change after enabling the setting, and after disabling the setting, changes in rotation are not applied. Setting all values to zero in the details panel re-enables the ability to rotate the component.