Reverse DNS lookup spam

Hello, I've just finished installing Pi-hole + Unbound in a Docker container on my RPi4B. Everything seems to work fine except for the fact that I'm getting up to a 1000 (limit) PTR queries every hour coming from the new Docker network that only Pi-hole and Unbound are in (172.19.0.1). These are all aimed at the 240.253.168.192.in-addr.arpa domain, which contains the local IP-address of my desktop computer.
Other rDNS domains are also in the list, but only once every hour which I've read normal Pi-hole behavior.

My Pi-hole does not function as DHCP server, as only my phone and PC have it set as a DNS server. Conditional Forwarding is enabled as that seems recommended for a setup like mine?

I'm not sure how to further investigate the cause of this, and whether or not this is problematic behavior or a mistake in my setup. I'm hoping that you can further educate me on this matter and help me solve any potential issues.

I did see a bunch of similar threads, but they were mostly over a year old and had different setups than I did. They also didn't contain any obvious solutions to me.

Debug token: https://tricorder.pi-hole.net/yDGlraXK/

A few hours after going to bed it stopped targeting my desktop and instead started with my phone at 241.253.168.192.in-addr.arpa. Some information that might be useful here is that I'm routing all of my phone's data through Wireguard with PiVPN which uses a different IP address.