GWT finds non-existent urls and says they come from whitin

Question

On our website, Google Analytics says the page http://www.example.com/culturel/index.php exists. But it doesn't and we return a 404 (visually and as a HTTP response). The correct page is: http://www.example.com/culturel/

But when I look in the analytics, it says that the page exists and even got thousands of views!
I even looked at the referrers and it says they are, among others:

• (not set)
• / [this is a valid page but I cannot find the bad link on it]
• /l.php [this is not a valid page on the site, it returns the 404 too]
• /programmation/ [this is a valid page but I cannot find the bad link on it]
• ...

On all of our pages, the link /culturel/ is present in the menu and is the correct one. It also is in the side bar on some pages but it is correctly written.
But it seems the crawlers find /culturel/index.php somewhere...

Is Google Bot just inferring that the page should exist and tries to crawl it on its own? (It thinks /culturel/ is a folder and tries index.php inside?)
Also, why would it say that the referrers are those pages since the link really is not present on the page?
And finally, why would it consider it as a good page when it correctly gives a 404 since forever?

Answer 1

My collegue figured it out.
As stated here: http://www.lunametrics.com/blog/2015/09/04/google-analytics-default-page/, it was because we had set the google analytics Default page to index.php in the View Settings of that website.

In our case, we shouldn't have done that since we do not use /index.php in the subdirectories.
So, please be aware that if you set up that field, Google Analytics will consider any directory to have that page available (and not juste the main directory of the website).