Set ruleFields variable from Supervised rules instead of hardcoded list
Smarty template of Contact form included commented line {*$ruleFields|@json_encode*}
https://github.com/civicrm/civicrm-core/blob/31ca8316cbcdbfba51b9295d9598d71811b7f308/templates/CRM/Contact/Form/Contact.tpl#L267 and hardcoded list of fields.
This is a reason of unexpected behauvior because Supervised rules are not used during creating new contact with option Check for Similar Contacts [ While Typing ]
Below method returns sql column names instead of names in api naming (custom_*) - this is a problem for api contact.get in Contact.tpl
$this->assign('ruleFields', CRM_Dedupe_BAO_Rule::dedupeRuleFields($ruleParams));
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information