Alaska Airlines site failures with NextDNS

Their site has a zillion trackers, performance measurement, A/B testing, and all the other crap. And somehow they've wired it together such that if some of that doesn't load or work then parts of their site fail - basics like searching for plane tickets. 

I know it's their fault, but.. even if I explicitly add all the crap to the allow list the site still doesn't work. And even if I go and turn off all the security and privacy protection settings in NextDNS it still doesn't work. 

The only thing that does work is entirely by-passing NextDNS and using Cloudflare or Google DNS. 

I can't figure it out - nothing in the logs, but is completely repeatable. 

Veering off topic, but a nice feature would be a quick single-toggle disable/bypass mode so that DNS requests were forwarded to a chosen provider. Back when I was using PiHole I think it had a similar feature that made it easy to debug or at least answer "is it DNS?" (it's always DNS)