First step is asking a support question to theme developers. Where we can find a JS code which changes drop-down values on page load.

This theme should be fully scanned for "select" or "change" word in all files in order to find the piece of code which does this.

Also this maybe cased by advertising JS functions. When you change theme the ads are not there so it's not clear which is the problem-causer. I'd recommend to disable ads on forum page as well.

ok I will look into it in a few hours, thanks for the ideas!

I'm the theme developer so there's no one to ask 🙂

I checked to see what's the problem and it seems whenever Advanced custom fields PRO is active it happens, when I deactivate the plugin the problem is gone.

I only have active fields on the footer that has nothing to do with any redirection, I guess I'll have to compromise and work without ACF on my footer so it won't have that problem and I will be able to keep the forum.

Unless this is something you know how to fix maybe?

Thanks!

Thank you for letting us know. We don't have any information regarding this.