Hmmm. Speaking of Fediverse interoperability, platforms other than yours (Pandacap) typically arrange things so that https://pandacap.azurewebsites.net was the domain, and something like https://pandacap.azurewebsites.net/users/lizard-socks was the user, but Pandacap wants to use https://pandacap.azurewebsites.net for both. Combined with the fact that it doesn’t seem to support /.well-known/nodeinfo means that no other platform knows what software it’s running.

When your actor sends something out, it uses the id https://pandacap.azurewebsites.net/, but when something tries to look that up, it returns a “Person” with a subtly different id of https://pandacap.azurewebsites.net (no trailing slash). So there’s the potential to create the following:

1. https://pandacap.azurewebsites.net/ sends something out.
2. Instance hasn’t heard of that, so looks it up, and creates a new user in its database, with the returned ID (https://pandacap.azurewebsites.net)
3. https://pandacap.azurewebsites.net/ sends else something out. Instance looks in it’s DB, finds nothing, so looks it up and tries to create it again. The best case is that it meets a DB uniqueness constraint, because the ID it gets back from that lookup does actually exist (so it can use that, but it was a long way around to find it). The worst case - when there’s no DB uniqueness constraint -is that a ‘new’ user is created every time.
4. Repeat step 3 for every new thing you send.

If every new platform treats the Fediverse as a wheel that needs to be re-invented, then the whole project is doomed.

Yeah, I know what you mean. That note is misleading, and kinda redundant too - you can physically de-select Undetermined in the UI, but the change won’t actually take if you press ‘Save’.

Most likely reason is that you unticked ‘English’ as a language you understand when you were playing around.

Firstly, sorry for any potential derailment. This is a comment about the Markdown used in your post (I wouldn’t normally mention it, but consider it fair game since this is a ‘Fediverse’ community).
The spec for lemmy’s spoiler format is colon-colon-colon-space-spoiler. If you miss out the space, then whilst other Lemmy instances can reconstitute the Markdown to see this post as intended, Lemmy itself doesn’t generate the correct HTML when sending it out over ActivityPub. This means that other Fediverse apps that just look at the HTML (e.g. Mastodon, KBIN) can’t render it properly.
Screenshot from kbin:

Also, if you add a horizontal rule without a blank line above it, Markdown generally interprets this as meaning that you want the text above it to be a heading. So anything that doesn’t have the full force of Lemmy’s Markdown processor that is currently trying to re-make the HTML from Markdown now has to deal with the ending triple colons having ‘h2’ tags around it.
Screenshot from piefed:

(apologies again for being off-topic)