Seen in multiple browsers on beta labs

We are creating an automated end-to-end test for AFTv5 running against a page on beta labs http://en.wikipedia.beta.wmflabs.org/wiki/Aftpage

One aspect of the test types a unique string into the feedback text box, saves it, and then clicks the 'feedback page' link in 'Your post can be viewed on this feedback page" after saving. The test waits 5 seconds for the posted feedback string to appear on the feedback page for the article.

The first runs of the test passed consistently. As the number of feedback posts passed about 50 entries, the test started failing intermittently while waiting 5 seconds for the saved feedback to appear. As the number of feedback posts approached 100, the test failed consistently waiting 5 seconds for the saved feedback to appear.

This behavior varies with connection speed and other factors of course, with slower connections taking a longer time. But the performance degradation noted here was seen on my local machine with a consistently good and fast connection, while beta labs was performing in a consistent manner. This behavior might indicate a real issue for very popular pages when AFTv5 is released to a large percentage of Wikipedia.

Version: unspecified
Severity: normal