Query log flooded with PTR requests

[lead0r]

I have two Raspberry Pis in my network.
Pi1 is running Home Assistant OS 12.2 with Adguard Home v0.107.48.
Pi2 is running Raspberry Pi OS with a bunch of Docker containers but no Adguard Home.
In my Adguard Home query log, I see a lot of PTR requests from Pi2 (hostname of Pi2 is raspberrypios which you will see in the screenshots).

Some of them are IPv6:

Others IPv4:

In the upstream DNS field in Adguard Home, I currently have only set 8.8.8.8 and 8.8.4.4.

My reverse DNS settings in Adguard Home look like this:

Adding my routers IP adress to this field does not change anything:

This still results in a lot of PTR requests. Next (with the routers IP still set as reverse DNS server), I added these lines to my upstream DNS servers:

However, that doesn't solve the issue either. Can anyone help me with this? Or is this related to Pi2 and I need to change anything there?

I found this similar issue: #3157
However, this was about two Raspberry Pis both running Adguard Home (as a reminder, I only have one instance of Adguard Home), and it actually was fixed

Edit: I noticed that not all of these are from Pi2, but some from my router as well