Just a guess, but some of the undocumented edge cases you saw might be explored in this blog from one of our software engineers, Shaun Thomas. It's all about conflict resolution & avoidance in PostgreSQL, in general: https://www.pgedge.com/blog/living-on-the-edge

If understanding how conflicts are handled in pgEdge is helpful, here's a link to the docs on the subject: https://docs.pgedge.com/spock_ext/conflicts

And the FAQ also delves into it some: https://www.pgedge.com/resources/faq