Carnegie, The Bill and Melinda Gates Foundation, and the National Council of Nonprofits guidance all have policies/guidance on conflict of interest that are publicly available (as highlighted in this comment).
Does Open Philanthropy also have a public document on its conflict of interest policy?
Given the prevalence of polyamory in the community (including amongst grantmakers) and the reported insularity / cliquey-ness of the Bay Area EA communities, I believe it makes sense for Open Philanthropy to make its internal policy on this public (and therefore open for critique).
I believe it also makes sense to show when policy may have been violated (especially in light of a rumour about a Senior Program Officer at OP and a grantee in a metamour-relationship being 'verified'.) I would find it hard to believe if the policy has never been violated across the 100s or 1000s of grants OP has made.
Given that the investment didn't go through OpenPhil, saying this involves a conflict of interest is a big stretch.