Reproduction steps:
1. Open attached project
2. Open Animator window
3. Select TestAnimator in Hierarchy
4. Click on the State1 in Animator window
5. Select each of the transitions in Transitions list - their different Exit Time is reflected in the preview
6. Click on the transition from State1 to State2 in Animator window
7. Select each of the transitions in Transitions list

Expected: their different Exit Time is reflected in the preview, as it's when they are selected via State inspector
Actual: their previews look the same

Reproduced on: 5.5.0f3, 5.6.0a1, 5.6.0f3, 2017.1.0p3, 2017.2.0b5, 2017.3.0a2