Even with a CDN, the IPs change frequently. Akamai, as an example, has a 20 seconds TTL on the IP that the client is connected to and that changes often. I don't think that would be a cause. The latency sure would.

Besides IP change, why do you think that a CDN change would impact the SEO? Curious to know your thoughts.

Also, when you say - 'The crawl rate is ramped up, post some experimentation.' What experiments did you run? Do share.