First load of metrics page notably slow

I noticed that when I loaded the metrics page in the UI, there was a long loading image (up to around a 15 count) whereas previously the screen loaded in a second or two. I reproduced this behavior in 3.29.2 but could not in 3.26.1 seemingly regression at some point (unless intentional). Filing for eval.

Nothing shows in nexus.log, js console or ?debug console.