sync watch not trigger

### Version
3.0.0-rc.1

### Reproduction link
[https://jsbin.com/qajepaniye/edit?html,console,output](https://jsbin.com/qajepaniye/edit?html,console,output)







### Steps to reproduce
rc.1 not trigger sync watch, beta.24 is work

### What is expected?
trigger sync watch

### What is actually happening?
 not trigger sync watch