The rotation widget and Rotation details sidebar have inconsistent values when rotating using the widget. Also, when hitting a 90 degree rotation from 0, 0, 0, the other axis values are affected.
Expected outcome: Rotation widget and Details bar reflect each others values and rotate uniformly
Outcome: Inconsistencies and errors with the other axis values when hitting around 90 degree rotation
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-27969 in the post.