For some reason VS Code has stopped automatically continuing lists, specifically in markdown docs. That is, while editing a list, pressing the enter key doesn't add another - or * to the next line.
I've been digging through settings and I'm entirely stuck on where to look. The only Markdown extension I have manually installed right now is MarkdownLint.
As far as I know, this is not a feature of the builtin Markdown extension of VS Code. At least- at the time of this writing, there is no such default behaviour, and looking through the list of settings, I don't see one to enable such behaviour. Indeed, googling "github vscode issues markdown list continue", I found https://github.com/microsoft/vscode/issues/117119, where this was raised as a feature-request, but the person who raised the ticket closed it when someone showed that is was possible through an extension- yzhang.markdown-all-in-one as an example (which I have no affiliation with).
Since you said you had this at one point before, perhaps you at one point had the yzhang.markdown-all-in-one and then accidentally uninstalled it- in which case you can just install it again.
Still, I'd be interested in seeing that issue ticket raised again, or a pull request, since it's possible that it could be implemented in VS Code itself through onEnterRules, though it might want some finessing to avoid doing it inside code blocks.