Resolution:
This product defect has been addressed/fixed in SPS version 6.
Once released, upgrading to SPS version 6 will allow for disjoining/rejoining of the domain within the WebUI successfully.
Workaround to Disjoin Domain:
Step 1 - Log into the core-shell console of the SPS appliance.
Step 2 - Run the following command to force the rejoin of the domain replacing the $user and $password with the correct values from the environment:
net ads leave -U $username%$password
Step 3 - Log out of the core-shell console
Step 4 - Log into the WebUI of SPS and ensure the domain is no longer joined.
Workaround to Rejoin Domain:
Step 1 - Log into the core-shell console of the SPS appliance.
Step 2 - Run the following command to force the rejoin of the domain replacing the $domain, $user, and $password with the correct values from the environment:
net ads join -s /opt/scb/var/db/joined_domains/$domain -U $username%$password
Step 3 - Log out of the core-shell console
Step 4 - Log into the WebUI of SPS and ensure the domain has been joined once again.