Yes, I think
When you are using a VPN, it must protect you, using their DNS, not a DNS that can rely on you.
An easy test :
Look at the DNS when the VPN is not activated, and then when it is activated.
DNS leaks is when some DNS activities are seen from your PC, not passing true the VPN path.
An example :
If I use DHCP (Dynamic Host Configuration Protocol), and activate Kaspersky VPN, it doesn't block some system / process to use other DNS.
=> I have to make some tricks to block some DNS to be used or in the long list of DNS given by Kaspersky VPN, I can see my IPS DNS
