Chrome /Firefox in multi step having different waterfalls

My coworker is doing tests in webpagetest with Chrome and Firefox using a multistep login. It basically uses clickandwait and execandwait.

We’re noticing responses with no requests. We thought possibly this was h2 push, but we don’t see same WPT behavior in a google chrome test.

Wondering if Pat would be willing to look at this, my coworker can send the private link if you’re interested in checking this out. Also wondering if maybe it’s just Firefox doesn’t handle this well?