Strange variations of my campaign links

I sent out a newsletter yesterday using the following campaign keywords:

Besides these, the following keywords are now displayed in my Matomo:

I have never used these campaign keywords - but the number of characters matches the ones I used and when I open the visitor log the corresponding pages are reached via the campaign links, that I wanted to link to.

Has anybody of you had this problem before? Could it be that these are bots? Or that it is due to some automatic ‘translations’?


The change looks similar to rot13 (shifting every letter by 13 places in the alphabet). As to why some software somewhere might modify the URL I have no idea.