Under what circumstances can such an url be obtained?

Question

PHP

Links on the site are generated automatically. The site is in php and it says:

...href="http://site.ru/page/'.urlencode(mb_strtolower ($page, 'UTF-8')).'"...

In most cases, everything is fine, the link is correct, but sometimes, Google webmaster tells me that a page with a 404 error was found, and gives the address of a non-existent page.
http://site.ru/page?%3F%3F%3F%2520Sami%2520Yusuf
Under what circumstances can the slash after $page disappear?

Answer 1

The address that Webmaster shows is definitely not the one that is generated in the link. Slashes don't disappear. Never.
It was formed somewhere else, and this is the place to look for.

Answer 2

The webmaster must have a source on which page the link was found.
And do not use such a construction, create a link generation class where there will be a method for creating links to page