This has been in place for some time, sorry I didn't report it earlier.
Loading the account creation page on beta labs http://en.wikipedia.beta.wmflabs.org/wiki/Special:UserLogin/signup (by way of redirect from http://en.wikipedia.beta.wmflabs.org/wiki/Special:CreateAccount)
yields an error from ResourceLoader for ext.centralNotice.bannerController
The code that checks for RL errors starts at line 20 of https://git.wikimedia.org/blob/qa%2Fbrowsertests/5b59eb8fd0ab0c841826f9a5bc8123290124a23e/tests%2Fbrowser%2Ffeatures%2Fstep_definitions%2Fcreate_account_steps.rb
A recent example of the error produced: https://wmf.ci.cloudbees.com/job/browsertests-test2.wikipedia.org-windows-internet_explorer_7/707/testReport/(root)/Create%20account/Go_to_Create_account_page__outline_example_____Special_CreateAccount___/
Version: unspecified
Severity: normal