Paul McCartney's birthday and caching bug on Wikipedia

As you may know, yesterday (06/18/2013) was the birthday of Paul McCartney (1942). I am not a big fan, so I was informed about it by the soc. networks - Vkontakte and Facebook. The only strange thing was that Vkontakte wrote that he was 71 years old, while on Facebook - that 70. I decided to verify this data with Wikipedia, and this is what was found.

Under the cut - the essence of the problem (nothing critical, but rather entertaining, in my opinion).


In my opinion, Wikipedia is to blame for this misinformation and this is why: open the English version of the article about McCartney ( link ) and you will see that his age is 70; open the Russian version of the article ( link ) and you will see that the age is 71 years old (just in case, at the end of the note I will provide screenshots confirming this).
')
The point is this:

1. If you look at the HTTP response request header to the English version of the article, you can see that the Last-Modified header contains the value Mon, Jun 17 2013 22:03:16 GMT. And the rest of the headings indicate that the content of the page has been cached;
2. if you look at the HTTP response header to the Russian version of the article, you can see that Last-Modified is Tue, 18 Jun 2013 18:29:03 GMT;
3. Now you can see the history of revisions of both articles and, indeed, the English version was edited on the eve of the birthday, and the Russian version - on the birthday of McCartney.

However, the age value should have changed in the English version. Let's try to get the latest version of the page by adding to the request "?" ( link ). It really helped - the correct age is now displayed (but not on the original page without the "?").

Problem summary: Wikipedia does not track the date and time of a page change when changes occur in automatically calculated fields.

Findings:

• I checked a few more articles containing automatic age calculation, and the problem is repeated in some of them. So, the age from Wikipedia can not be unconditionally trusted :-)
• You should take into account all the dynamic content on the page when developing a caching system. As it seems to me, the calculated fields on the Wikipedia pages were added later, after the caching system was created. And this system was not revised after adding calculated fields.
• The problem is not very serious, as it can be corrected over time by updating the article by any Wikipedia member. It is difficult to find articles that were edited for a long time and would contain calculated fields.

Screenshots:
Russian version
English version
English with "?" at the end of the URL

PS
I do not know if there are other calculated fields on Wikipedia that may be affected by the problem. Also, I do not know if Wikipedia has a bug tracker, and whether it is worth fixing the problem at all.