No sort arrows in header

Hi,

thanks for your question, and sorry for the late answer. As I was on vacation, I didn’t have a chance to reply earlier.

This is a theme problem, unfortunately. There’s a script being loaded by the theme (apparently to create some JS menu functionality), that is raising an error message. This unfortunately makes the browser stop executing the remaining JavaScript code on the page, including that for the sort arrows.
So, to fix this, you will need to fix that issue in the theme, either by asking the theme developer for help, or by switching themes.

Regards,
Tobias