Your router is advertising 2 DNS servers and your devices are probably using the other server on some queries, resulting in Pi-hole being by-passed:
router: 192.168.1.1
dns-server: 213.57.2.5
dns-server: 192.168.1.164
From: How do I configure my devices to use Pi-hole as their DNS server?
Pi-hole should be the only DNS server set here as Pi-hole already delivers the other upstream servers. If you set another server in your router, it's possible your ad blocking may be negatively affected.