Hello,
Very likely you choose the number of products per row that does not have the 3-rd page. For example, you opened 3-rd page and choose 27 per page, but there is no 3-rd page anymore if you choose 27 products per page, there are only 2 pages. We’ll try to fix it in future theme updates by resetting page to the first if the page where you chose the number does not exist anymore.
Regards