Hello,
We use the default parameter for the brands permalinks in /et-core-plugin/inc/post-types.php
https://prnt.sc/hpgv9z
It’s not possible to save changes for the brand permalinks without this parameter, that’s why we use it. You may try to change it to 'rewrite' => false,
re-save permalinks after that and check if it helps in your case.
Regards