Background
I was told in chat that some sites don't / might not see self-answers in a positive light, which I found surprising, having read the (fairly old) "It’s OK to Ask and Answer Your Own Questions" blog post, which is linked-to directly in the Ask Question UI, and the "Can I answer my own questions, even if I knew the answer before asking?" FAQ post here on MSE. It made me wonder- Is it truly the case that some network sites don't receive self-answers and self-answered-questions well? And if so, why?
"Research"
One (completely baseless!) theory I thought of to possibly explain this (if it really exists) is that experts like challenging questions, and maybe they dislike finding a question with self-answers they find satisfactory because it doesn't present a challenge to them / tickle their expertise bone. I strongly suspect that this theory is wrong, but it was the first thing that popped into my mind, so I thought it to be worth stating so that it can either be constructively disproved or confirmed.
Question
Is it true for any specific network sites that there is a general stigma among the site regulars (particularly answerers- i.e. the experts) against self-answers? (disapproval of / "discrimination" against. For example, disapproval that materializes as downvotes) Or do any specific network sites have different, specific etiquette/guidelines for self-answering? If so, for those sites, why?
Purpose
I'm asking this because I want to participate on the network with good etiquette and to be forewarned-about / mentally-prepared-for running up against any stigma against self-answers.
Finer Details of the Question
I'm not talking about self-answers where the question or the self-answer have issues that violate official Stack Exchange-wide or widely-accepted-on-site-specific-meta community guidelines. I'm talking about stigma particularly and only against the fact of the Q&A being a self-answered one: Questions that stand alone as well-formed, on-topic, not-too-localized, good-fit-for-SE questions, and self-answers that stand alone as well-formed, complete, useful answers. This question is not a duplicate of "What are limitations on self-answered questions?" or the similar post on MSO: "What are the limits for self-answers? When are they (not) acceptable?"
I'm not talking about self-answers to questions where the answer to the question could be found outside the SE network in a short time (for example, 5 minutes) by googling the title. I don't think a large volume of such Q&A posts would really serve the goal to make the internet a better place.
[puzzling.se] and [codereview.se] are out of scope for this question, since puzzling has a loose "protocol" / etiquette for self-answering, and so does codereview, and both are quite different beasts than the other more conventional knowledge-sharing network sites.
I have tried to pose this question following the guidelines for asking constructive subjective questions. Prefer sharing experiences rather than opinions. Back up any opinions with facts and references. Keep in mind the purpose for which this question is asked. If you know that any network sites that have specific etiquette/protocols for self-answering like [puzzling.se], please link to them and summarize their rationale.