在Unity中，动画混合时的旋转方向问题通常是由于动画状态选择了最短的旋转方向。在Spine的预览窗口中，通常会选择最短的旋转方向进行混合，这可能与Unity中的表现不一致。为了在Unity中实现与Spine预览一致的效果，可以尝试以下方法：

1. 调整动画的起始或结束旋转：在动画的结束时间减去混合持续时间的位置调整旋转，或者在下一个动画的开始位置调整旋转，以便在混合开始时选择另一种旋转方向。

2. 使用中间动画：创建一个中间动画，确保骨骼以期望的方向旋转。可以在检测到混合可能导致问题时使用中间动画。

3. 使用TrackEntry的resetRotationDirections或shortestRotation：在Unity中，使用resetRotationDirections可以在混合开始时重置旋转方向，或者使用shortestRotation来始终选择最短的旋转方向。

通过这些方法，可以在Unity中实现与Spine预览窗口一致的旋转混合效果。

@fivestar TrackEntry.ShortestRotation can be set at the TrackEntry object that is returned from calls to AnimationState.SetAnimation or AnimationState.AddAnimation.

It might also be the case that you've keyed an undesired rotation value outside your desired 0-360 degrees accidentally in your animation. Please note that the active Axis mode is relevant when setting rotation keys, Local and Parent allow you to set rotation values ending up, while World will set an angle clamped to 0-360 degrees.
http://en.esotericsoftware.com/spine-keys#Bone-transforms

@fivestar The shortest rotation is used by default. The ShortestRotation property just defines whether the shortest rotation is defined once at the start of an animation mix, or whether it's always re-evaluated, thus leading to potential change in direction midway. See the documentation text:

If true, mixing rotation between tracks always uses the shortest rotation direction. If the rotation is animated, the shortest rotation direction may change during the mix.
If false, the shortest rotation direction is remembered when the mix starts and the same direction is used for the rest of the mix. Defaults to false.

@fivestar If you see strange behaviour of e.g. going round twice with simple mixing, then the keyed rotation values might likely be keyed with more than 360 degrees difference. E.g. one animation keyed at 180 degrees, and one at 450 degrees. Did you check the keyed rotation values with axis mode Local or Parent?