Bug in CNAME Flattening causing nextDNS to not block ads?

hi there. I've been trying to chase an issue for a few days and I finally got it solved. Whenever I would go to say CNN.com I would always see their ads in Safari but not in Firefox. I have nextdns installed at the command line, not using the app in this case, and had my dns set to 127.0.0.1 as required. After much sleuthing I figured out that something with the CNAME Flattening being on was causing this. See my test below:

W0299 ~ % sudo nextdns config edit (using eb199d profileID)

W0299 ~ % sudo nextdns restart    

W0299 ~ % nslookup doubleclick.net

Server: 127.0.0.1

Address: 127.0.0.1#53

Non-authoritative answer:

Name: doubleclick.net

Address: 162.250.7.137

(Solves fine and doesn't block ad)

Turn off CNAME Flattening

W0299 ~ % nslookup doubleclick.net

Server: 127.0.0.1

Address: 127.0.0.1#53

Non-authoritative answer:

doubleclick.net canonical name = blockpage.nextdns.io.

Name: blockpage.nextdns.io

Address: 162.250.7.137

Shows the block page fine.

I had a second profile that was having that issue, so I ran the same test again, and sure enough it passed the first time and blocked the domain the second.

So to be sure I turned CNAME flattening back on and sure enough no block page:
 

W0299 ~ % nslookup doubleclick.net
Server:        127.0.0.1
Address:    127.0.0.1#53

Non-authoritative answer:
Name: doubleclick.net
Address: 162.250.7.137

I'll keep it off but thought you might want to know something is not right here.