How to reproduce:
1. Open the attached project
2. Find "Male_BaseRig_00" model in the Project and reimport it
3. Open and play AnimationPreviewTest
4. Notice that animation has very small hiccup
5. Open SwingTest animator controller in animator window
6. Click on the transition between Male_LongIron_RegSwing_Forward and Male_LongIron_Reg_FollowThrough states
7. Preview the animation
8. Notice that animation has big hiccup during transition

Expected result: Animation playing in preview window and the scene should give the same result
Actual result: When animations have zero duration transition animations differ in preview window and the scene

Reproducible: 5.3.6p8, 5.4.2p3, 5.5.0b11, 5.6.0a2