Creating Anim Montage drops a frame(s)

When creating an animation montage, it appears that frames can be lost.

1. Download the attached project
2. Open The animation sequence "Cube_1SecondSpin_Anim" (it will have 30 Frames)
3. Open "Cube_1SecondSpin_Anim_Montage"

Result: The Montage has less frames (dropped by one in this case)
Expected: The montage would have the same number of frames