To reproduce:
1. Open attached project;
2. Open "case_1" scene;
3. Select "root" game object in the Hierarchy;
4. Open Animator window and select "Layer2" layer in the Layers tab;
5. Select "rotate" state;
6. Make sure Motion of this state is empty (None);
7. Enter Play mode;
8. In the Parameters tab (Animator), tick a checkbox "Mixed";
9. Look at the Game view to see results;
10. Go to the Animator window again, select "Layer2" and select "rotate" state;
11. In the Inspector, set the Motion of the state to "clip_2_rot";
12. Tick a checkbox "Mixed" in the Parameters tab;
13. Compare the results.

Expected result: all of the cubes slide to the right and then rotate 45 degrees to the left.
Actual result: all of the cubes slide to the right, but only the third cube rotates.

Reproduced with versions: 2017.1.3p2, 2017.2.2p1, 2017.3.1p4, 2018.1.0b10, 2018.2.0a4.