The short answer: Yes, ELB's IP addresses (both the ones that are publicly distributed to clients of your service, and the internal IPs from which ELB sends traffic to your instances) dynamically change.

Does AWS alb have IP address?

However, Classic Load Balancers and Application Load Balancers use the private IP addresses associated with their elastic network interfaces as the source IP address for requests forwarded to your web servers.

How many IPs does AWS ALB use?

A single DNS lookup for a load balancer will only return up to eight IP addresses. So, if you have an ALB that has more than eight IP addresses, you need to perform multiple DNS queries to be sure you have all of the addresses.