cia @rjalex !!
Awesome question! Thanks!
I noticed that articletitle is also tokenized as word, so “attentato” has 3 hits.
Two in prose, and one in articletitle.
the other object has “2.3” hits (1.3 prose and 1 in articletitle ) hits and a “attentatore” that I don’t believe matches.
But that doesn’t explain the “trump” part 
One wild guess: if you change the order of the words, do you get the same results?
Also, if you run bm25, will you get same scoring?
Thanks!