I installed a 6.4 snap25 satellite and have hit a bug getting it to join kickstarting machines to my IDM realm.

The relevant part of the "kickstart default" template says:

<% if host_enc['parameters']['realm'] && @host.realm && @host.realm.realm_type == 'FreeIPA' ->
<= snippet 'freeipa_register' >
< end -%>

but there is no option in the Realms creation page to create a "FreeIPA" realm_type, instead you get "Red Hat Identity Management" so the snippet is not called.

Updating the kickstart to:
<% if host_enc['parameters']['realm'] && @host.realm && (@host.realm.realm_type 'FreeIPA' || @host.realm.realm_type 'Red Hat Identity Management') -%>

should be enough to fix the issue