Hi,
When you have your PE enabled for any Service, when you try to resolve the FQDN of the service from a Source which is outside of your VNET which is linked to your Private DNS Zone, it will resolve to the Public IP of the service instead of the Private Endpoint IP.
So you will need to setup your On-Premises DNS to resolve the FQDn to Private Endpoint's IP. Or you will need to forward the DNS queries to Azure where you can setup Private Resolver: https://learn.microsoft.com/en-us/azure/dns/dns-private-resolver-overview
Regards,
Karthik Srinivas