I think the confusion may arise from the term ‘decay’

Decay is normally used to describe radioactive decay where by an unstable isotope tries to loose energy by giving off alpha beta gamma radiation and all permutations of.

Hence if you ask what Uranium is decaying into, you will get the appropriate uranium isotope decay chain, which is a sequence of small steps. Also what was described in the link provided was what happens when a uranium atom absorbs a slow moving (thermal) neutron and gets a bit more energy, so it can then in turn decay into Np and Pu.

If you ask what the fission products of uranium are the answer will be a bit more dramatic. The fission products are the two, almost equal mass atoms formed by the spitting of the initiating nucleus. If you add up the mass of the fission products and the mass of the neutrons , alpha beta particles and neutrons, add in the kinetic energy of those plus the mas equivalence of the energy released in gamma radiation and heat etc you should get back to the original uranium mass (plus or minus some picky points).

The exact split depends on the energy of the incident neutrons and the parent atoms, but generally speaking the fission products will lie in two groups , one with atomic mass in the 90-100 range and the other group in the 110-140 range. For any given big fission event you will have quite a mix of product elements. These will all be quite energetic and have a lot of excess neutrons themselves so are quite likely to decay into more stable isotopes (more being a relative term) so the exact answer to what is left after an fission event is more of a mix of isotopes rather than any two specific isotopes.