Control rig blueprint spawns with Event Graph rather than Rig Graph when 'Spawn Default Blueprint Nodes' is false

It seems that disabling the 'Spawn Default Blueprint Nodes' editor preference results in control rig blueprints being created with event graphs rather than rig graphs. It doesn't appear to be possible to then create a rig graph so any users that have this option disabled will be blocked from using control rig. This effects both 4.26 and ue5/main.

1. Open the editor preferences and disable 'Spawn Default Blueprint Nodes'
2. Create a new control rig bp and open it
   1. Note how you're presented with a Event Graph rather than a Rig Graph