Rotation values are reset to 0 (zero) when first Scale key is created.
Scrubbing the timeline forces a refresh, eval and correct rotation values are updated.

repro:
-create a cube
-create a new clip
-select the cube
-move and rotate the cube in the scene view to create a first Position & Rotation key at time 0.
-scale the cube in the scene view to create a key... Rotation values are reset to 0 and cube orientation is reset in the scene view (bug).
-Move the timeline in the AW, rotation values are now evaluated properly.

this is a regression from 5.3
works properly in...
Version 5.3.2p2 (dec88fd2a56c)
Mon, 01 Feb 2016 22:20:45 GMT
Branch: 5.3/patch-release

repro in...
Version 5.4.0b5 (60658ab74c44)
Branch: 5.4/release