I'm noticing that DomContentLoaded, Processing Time, and Load Time are all blank for Reddit withoutout uBO as well.

I'm going to make a mild suggestion that the author double-check their implementation logic. Is it possible that the ad-encumbered page isn't loading before it times out? Or is it possible that without ads the page is loading more content?

Even showing something like a comparison screenshot at the end might help in odd cases like this.

This was an old result from when the server didn't have enough memory for big sites (especially the version without uBO). I reran it for Reddit, you can see the result on the same URL.