Pihole malware alert

I am a novice PiHole user. Set one up as a DNS server for my home network which is a Unifi Dream Machine router. Upon installation I started getting messages from the UDM IPS that the pihole device is attempting potentially bad traffic to ET DNS Query for .su TLD (Soviet Union) Often Malware Related. Interestingly, PiHole is configured to us cloudflare, and not quad 9. I cannot link activity in PiHole logs to the UDM IPS alerts. Anyone out there have an ideas what this is all about?