Double check your various forms of links JIC. If you have done your work right, then there is nothing for you to do.
There are a ton of scrapers and sites that will make bad links and perhaps that is what is happening. It is not uncommon that site automation of this type to go wrong creating links that Google will see as new and follow.
Just make sure your work is right and be as thorough as you can. It is very easy to miss something- we have all done it- it can be embarrassing, but important to find. It might be worth while to use both a desktop and mobile device and walk around your site. Just turn off ads for a while as not to get into trouble.
If it helps, you can use ScreamingFrog which is free up to 500 pages or SEO PowerSuite which may do the same thing on a larger scale in trial mode. In that, you can use these tools to find broken links which is something you should do from time to time anyway. These tools will find mistakes that are easily overlooked. Again we all do it. I found some mistakes I thought I took care of a long time ago on my last audit.
