We have notice the following behaviour when using a domain to hit a search head
If we hit the search head directly using an IP address:
servicesNS/jared includes the username
/en-US/splunkd/__raw/servicesNS/jared/AccuHealthDoctorView/static/appIcon_2x.png
If we hit the search head during the domain
servicesNS/undefined does not include the username.
en-US/splunkd/__raw/servicesNS/undefined/search/static/appIcon_2x.png
The above behaviours prevents the appicon from loading.