Hello. Thank you for contacting the Toolset support.
If the target is that any date that contains value "31/12/21" that you change it to permanent then what if you add the following code to your view's JS section.
I do able to change the date from 31/12/21 to permanent when the View is first time loaded but date will be resumed back to 31/12/21 when I click the reset button.
Can you please share problem URL where you added the view and admin access details so I can check whats going wrong with your setup.
*** 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.