Hi,
Thank you for the details!
It looks like the output of the search is altered. I am seeing multiple paragraphs and removed HTML tags in the page source. It looks like the category description field is probably furhter processed or not fully supports shortcodes.
By default WordPress category descriptions does not support shortcodes, only plain text. If you are using some sort of a custom code to allow that, you may have to check that. A similar issue is reported here, they resolved it by removing a specific filter hook from the term description code.