After the test, I unblocked Aleksey, and this tweet includes the video where we saw that Aleksey could see my tweets in his timeline again. Something went wrong after that I guess.
https://twitter.com/muratdemirbas/status/1062763863332937728
I described how the logic works above, but we're always subject to and victims of replication or cache-expiration latency. So it could have been that.