The error also happens with Firefox ESR 52.9.0, Vector skin on my age-old Windows XP SP3 system. After the date field is emptied manually, its display changes to light-grey "YYYY-MM-DD" format information (I am assuming this would be the correct default status), and further searches in the actual page work. Once the log page is closed and re-started, the same issue happens again unless the date field is cleaned up again first.

Welcome back: https://commons.wikimedia.org/wiki/File:Yaroslava_Shvedova.JPG

Possibly another related case reported by a different editor: https://commons.wikimedia.org/wiki/File:Yaroslava_Shvedova.JPG, mentioned at https://commons.wikimedia.org/wiki/Commons:Administrators%27_noticeboard#File:Yaroslava_Shvedova.JPG.

Agree to close. The original misunderstanding was clarified, and an eventual tweak is already discussed in a different task. Closing this (hope that's OK).

In T143742#2577506, @Sjoerddebruin wrote:

The given page contains the following:

{{#property:P106|from=Q42}}

Every change to the linked item of the page and the items that are being used on the page appear in the watchlist.

Error has been seen on en-Wiki in https://en.wikipedia.org/wiki/Cowcliffe and https://en.wikipedia.org/w/index.php?title=William_Young_(Wisconsin_politician) - both within the last 24 hours.

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.

A slightly different behaviour, which may be caused by the same underlying problem (just copying my note from en-Wiki):

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

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.

As a German I don't know how common the term is, but how about "Free-form"?
The problem with "Basic" in this context is: this citation form is not restricted to "basic" usage (aka simple or generic), in fact it can be the most complex method with additional options and flexibility in citation creation.

Thanks for the information, this issue (and related flaws in the CSS handling) have been discussed at en-Wiki VPT locally as advised.

Aside from the best name, would it be possible to separate this function from the other "regular" templates with a horizontal divider line between "Basic form" and the rest of the templates? This would clarify visually: "Basic" is a citation, but it's a different type - separate from the others.

Quick update: purged per the advice on top of this thread (thanks) and Citoid and regular UI are available again.

Currently Citoid is down for me at en-Wiki (FF 39.0, Windows XP, vector skin, desktop).
The main menu shows "Cite" with the usual small arrow to open the menu.
Inside the menu the list shows as a plain list with only 1 column: Website, Book, News, Journal, Basic, Re-use with their respective icons to the left. No "Citoid" function at all.

@Jdforrester-WMF I don't understand what you mean by 'they get an "Edit" button immediately)'. Users currently don't get an immediate "Edit", they have to "Insert" the citation (even if they know full well, it is wrong or incomplete), and only then can re-enter the "Edit"-mode. This non-intuitive extra step is far more disadvantageous than some assumed rare misclicks. Currently, and in the foresseable future, most Citoid references need a bit of polishing and fixing afterwards - this is the more common ''standard'' case. The UI layout should support a convenient way to handle this standard situation.

(I originally filed this bug on en-Wiki)
No console message is displayed, when I save the article (Windows XP, FF 38). But when I started the editing session with VE earlier, and it was loading the article ("Hockenheim" on en-Wiki), I noticed the following error in FF console:

See en-Wiki feedback "Citation numbers messing up". This problem is repeatedly mentioned on en-Wiki, confuses editors and hinders editing of developed articles with complex reference structures. I would like to propose the whole issue with "references in templates" and "references generated by templates" as blocker. I am aware, that 5 other tasks are possible related to this problem (See also), maybe the whole topic area needs another fresh look for a solution. - the problem is known for almost 2 years now, and should get a higher priority and more frequent updates on its status.