This is a short article from 2015 which discussed how the Caluza ruling introduced adversarial factors into the VA's non-adversarial claims process.
Daniel L. Nagin, The Credibility Trap: Notes on a VA Evidentiary Standard, 45 U. Mem. L. Rev. 887 (2015).
https://dash.harvard.edu/bitstream/handle/1/27814585/Nagin_CredibilityGap.pdf?sequence=1