Loaded by/Initiator for base page is unexpected

I would expect the initiator to be empty for the base page in this test, but it contains a script which is loaded after the base html. Is this expected/explainable somehow?

https://www.webpagetest.org/result/200313_JF_9a6b9840b1e7d426a41eeacc0884ebc4/2/details/#step1_request3