Bug when I use anima2d clip in timline ,it shows mess around

Unity version ：2018.4.30
When I put an Animation clip made by anima2d( especially when i used bone component) on the animation track,the animationclip in behind was always influenced by the clip in the front.It's
looks messed around. It seems that the position of the bones in behind animationclip had been blended with the bone's position in the front clip,even though I haven't used any blend between these two clips.
In general,this issue always happened between two clips that used the same bones ,and they looked fine out of the timeline.