Thanks for adding this task. To clarify a bit: not only the "Autovalue" function is not working, the whole TemplateData content is apparently not loaded. I get the standard message "You are adding the "Cn" template to this page. It doesn't yet have a description, but there might be some information on the template's page." for missing TD info from VE, even though the template has such data. I don't know, how exactly VE loads the TemplateData information from the original Template page, but somewhere along the way it gets lost (currently it's still not available for Template "cn" on en-Wiki). Other templates on en-Wiki work fine.

Hmm. Intermittent load issues are horrendous to track down (just see T93800: Messages randomly missing in some languages when populating MessageBlobStore).

Yay edit conflicts.

(T78236: Phabricator silently overwrites changes (no mid-air collision/conflict detection).)

Sorry - didn't mean to mess up the task info.

In T111230#1598815, @GermanJoe wrote:

Sorry - didn't mean to mess up the task info.

No worries, totally not your fault.

It's not working for me ATM as well, in both articles and sandbox.
FYI though https://en.wikipedia.org/wiki/Template:Citation_needed_span works, if someone needs a dirty workaround.

Existing TemplateData for this template is still not loaded via VE.
I could try to request another null edit on the template, which might fix the problem. But it's probably better to retain the current error situation for further research.

enwiki's {{Citation needed}} is working for me right now.

I dunno if my T117164: VisualEditor thinks there's no templatedata for my template with /doc subpage woe is related. In that bug, the template doesn't have a templatedata pageprop, only its /doc subpage does.