Hello. Thank you for contacting the Toolset support.
Well - when you try to add a taxonomy filter - taxonomy filter does not support the custom value as well as display_values. There is no such feature available as you can see with the following screenshot:
=> hidden link
You need to add normal taxonomy filter without value and display_values as its not supported.
That is really strange. Can you please share access details.
*** Please make a FULL BACKUP of your database and website.***
I would also eventually need to request temporary access (WP-Admin and FTP) to your site. Preferably to a test site where the problem has been replicated if possible in order to be of better help and check if some configurations might need to be changed.
I have set the next reply to private which means only you and I have access to it.