Not sure how I missed this before...
SSD was adding the domain to the user when doing a nss user lookup. You can see this by viewing the output of
sssctl user-checks <USERNAME>
Changing the default full name format via the sssd.conf removes this behavior, which in my case is desirable. You may not want to if you are in a multi domain environment. Buyer be ware.
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/htm...