Why is this additional string appearing in my product URL and how can I remove it?

[Karen14]

I am used to seeing additional strings on our product URLs when the product is out of stock - or for some reason, a duplicate product page was made, but I have never seen this one - ?_pos=2&_sid=0ce38240f&_ss=r.  Does anyone know why this is appearing and how to get rid of it? Thank you.