Steps to reproduce:
0. Go to en.wikipedia.beta.wmflabs.org
- Log into an account with a user_id where mod 4 results in 1.
- Go to http://en.wikipedia.beta.wmflabs.org/wiki/0.5841116106330823
- edit the page and click save
- See no post-edit -- console shows "Uncaught TypeError: Cannot read property 'setId' of undefined"