The idea for the second season’s title must include all of the original title in Japanese, Rikei ga Koi ni Ochita no de Shoumei Shite Mita.
You can’t shorten the title itself or insert original phrases between them like — Rikei ga Koi ni Ochita or Rikei ga Koi ni Ochita no de 〇〇Shoumei Shite Mita.
With that in mind, the two drag everyone else in the lab into trying various experiments to prove love actually exists.