You have created a static route for 8.8.8.8 (which is the IPv4 for one of G**gle's DNS servers). Any packet (not just DNS requests) destined to that IP address will be delivered to 192.168.0.6 instead.
A better way may be to configure your router to redirect all DNS traffic (port 53) apart from your Pi-hole machine's own to your Pi-hole machine.
That way, all DNS requests from your network clients would be forced through your Pi-hole, regardless which DNS server a client would try to get to (including G**gle's 8.8.8.8).
Not all routers would expose respective configuration options for their firewall.
If redirecting DNS isn't supported, you may be able to at least block outbound public DNS requests, again excepting your Pi-hole host machine.
As far as Talkatone is concerned, re-routing 8.8.8.8 may not contribute to your observation at all.
How do I determine what domain an ad is coming from? may help in finding domains that would be blocked by Pi-hole.