animation-curves.js:174 Uncaught TypeError: from.lerp is not a function
at cc_DynamicAnimCurve.12.cc.Class._lerpVector (animation-curves.js:174)
at cc_DynamicAnimCurve.sample (animation-curves.js:236)
at AnimationState.14.proto.sample (animation-state.js:432)
at AnimationState.process [as _process] (animation-state.js:272)
at AnimationState.14.proto.update (animation-state.js:350)
at CCClass.update (animation-manager.js:44)
at 56.cc.Scheduler.update (CCScheduler.js:413)
at 51.cc.Director.mainLoop (CCDirector.js:965)
at callback (CCGame.js:643)
2d项目，刚从2.0.10升上来，播放动画的时候报这个错，跟踪了一下发现from这个对象是个cc.Vec2，看了下文档里cc.Vec2是有lerp方法的，但是调试的时候看到from这个对象并没有lerp方法，请问是什么情况？