I basically have the same problem as in CiviDiscount Navigation URL incorrect not for a special extensions though, but for the search. I'm using CiviCRM 5.44.0 on Wordpress 5.8.2. I added this url to a new navigation item:
When using the menu item it navigates me to:
The important characters are just converted to underscores. Is this a saftey setting I have to disable?