Really shows how even if you're using a big cloud provider, you're not safe from sudden systematic issues like a backing service becoming unavailable. I wasn't aware they directly integrated third-party providers like that.
There's an Azure migration path from Azure CDN to Azure Front Door.
I'm not too familiar with the Azure products. Surely Azure CDN was documented as backed by another company, and mindful use would have been aware of this provider dependency?
Still, I feel like the uniform Azure branding nudges users to trust it as one big, stable, long-term platform that can serve all your needs.