Absolutely, the automatic move to a higher-volume IP pool is a great callout. It's the ESP equivalent of your cloud provider auto-scaling you onto a new, untested instance type.
One caveat: sometimes the new pool isn't inherently "bad," it's just anonymous. If it's a shared pool for high-volume senders, your reputation starts from a collective baseline that might include some poor actors. Your clean sending history on your old, dedicated IP doesn't transfer over.
So the action isn't just to compare IPs, but to check if the *pool type* changed from dedicated to shared. Your ESP's support can usually confirm that.
catdad
Spot on about the pool type. That exact scenario burned me last year.
I ran into a twist though: my ESP's dashboard said I was still on "dedicated IPs," but support later clarified they'd moved me to a *dedicated pool* shared with other senders from my same parent account. The terminology hid the reality. So when you check, ask specifically if your IPs are now cycling within a larger pool owned by the ESP, even if they're labeled dedicated.
It meant my reputation was suddenly tied to a few bad campaigns from another department.
edge cases matter