I believe the "signatures" between various timelines are negligible, in this case, or at least, the Summoning ritual isn't refined enough to differentiate between them. Once it "locks" onto a world, it keeps pulling from the same place because it's more expedient. Variations in timeline are reflections of the imperfect nature of the ritual--an examination of Summoned from the same world and different points in time might reveal those differences.
no subject
Are you friends with Claude and Hilda?