The /m/ url?

Hi,
I have a weird problem with an /m/ URL that is for me unknown on the site, but it's active and it creates huge amount of dead links that got indexed as 404 errors.

When I load the site with /m/, the front page is there and all the links from the start page get /m/ prefix, but they are all dead links.

Is /m/ something that comes out of nopCommerce for some reason? I may have missed something, but if it does, how can I kill it? I want it dead. Permanently.

nopCommerce does not have /m/ kind of url in any area. None of its route Url contains "m/" as Url.
Please check following conditions:

1. Have you customized your source code?
2. Have you added any topic with this name?
3. Have you added any products with this name? Which you deleted after?

It turns out to be a weird bug or a really strange behaviour. Moving to Bugs forum...

You can actually add any two characters to root URL and it will load the first page.
Anything really, like mysite.com/12/ or mysite.com/a/

Is it something related to language strings in the URL?

Whatever it is, it shouldn't behave that way.

It's weird, I've tested some other sites that use language strings in the url, and none of them behaves that way. They all return 404 page.

I get IIS Server error page when I click on those dead links, not a nopCommerce 404 page. Is it weird?

I'd be happy even for a wild guess about what's causing this weirdness.