AWS AMI Creation Stuck for a long time even after EBS snapshots are available (100%)

We are using EC2ImageBuilder to build AMIs but the AMI creation gets stuck after the EBS snapshot are created (available 100%). There is also no visibility to track the progress of AMI creation. The same AMI creation (with exactly same configuration) was being completed within an hour couple of days back.

Are there any additional time intensive steps taken post snapshot creation for building AMI? And is there a way to track the progress, root cause and speed up AMI creation?

Instance configuration : (EBS Volume size : 50gb, instanceType : g4dn.8xlarge)

(PS: We are using ecs optimized gpu AMI as base AMI and the only additional step is that we're downloading a docker image (~ 15 GB) before taking snapshot)