First of all, I am not an expert (23, Mechatronics grad mostly focusing on Electronics and Hardware) all we can rely on are published documents that we can read.

As we delve into practical answers and from several references that I skim-read through, the correlation between older nodes and reliability exists however enhancing the fabrication process is possible.

This article provides a good write-up regarding the common knowledge of radiation and IC. Ultimately, we shouldn't overthink what engineers are doing unless we also have a specific interest/being part of the project. Reading/Learning something is fun as long as you know the limit of what you can process at the time and at the same time have the limit of what you should read and should not. Again, I am not an expert; I only provide knowledge that is published and based on my limited understanding. Besides I found it interesting to dig for information from published documents :)

As much as skepticism, MIPS itself is old. Besides, good press (yet they don't fully open the details) can boost their publicity (if you understand what I mean).

References:
Appendix Three: Space Radiation Effects on Integrated Circuits, NASA
Radiation effects in the electronics for CMS, Faccio, F., CERN
Common misconceptions about space-grade integrated circuits, Shunkov, V