In 3.15.3, some step details pages have loading errors, as seen in the attached screenshot. This issue appears to be limited to Cloud Service deployment steps (which use the older Azure Certificate accounts).
Thanks for getting in touch. I’m very sorry to hear the latest build broke your step. I was able to reproduce this and created a github issue for it: https://github.com/OctopusDeploy/Issues/issues/3653
Please follow that issue to get notified when we push a fix for it.
Apologies for the inconveniences caused by this.