https://www.sciencemag.org/news/2014/08/underground-experime...
Well ... yes, yes they did.
Pretty fascinating, if light, overview of what's involved in neutron detection. A case of understanding theoretical models (causal knowledge), materials, purity and processing, conversion processes (neutrino interaction -> light -> photodetector), statistics, and ultimately, a view of what was happenning inside the solar core eight minutes ago, events which won't manifest on the solar surface for another 100,000 years.
In the quoted example, "direct evidence" from that paper was not necessary to confirm that the other calculations and models match. The achievement presented in that paper was to measure the specific neutrino flux, but there were many other measurements before that matched the developed models and weren't less convincing.
It's always good to read more than only journalist's interpretation. Here's from the paper itself:
Eve before "solar neutrinos from secondary processes have been observed, proving the nuclear origin of the Sun’s energy and contributing to the discovery of neutrino oscillations."
Only "those from proton–proton fusion have hitherto eluded direct detection."
https://www.nature.com/articles/nature13702
The paper itself stated that the reactions in the Sun were already proved.