Thank you for your answer!@m_adam
Although object go back normal after i clicked 'Redraw' (I guess that's the reason),it isn't make sure problem is 'refresh the viewport'. 'refresh the viewport' can also fix Priority error result .
'Shift Priority Tag' just effective Expression.It can't help.
After asking questions,i try to use Python Tag to replace 'Spline Deformer Object' ,because Python Tag have Priority.Fortunately,even though it looks very complicated, but everything become ok!