I've been using Houdini for nearly 6 years - so I've decided to try my hand at the new APEX Rigging stuff

I am Rigging the Electra Character using the Skeleton and Rest Geometry from the "Test Geometry: Electra" SOP, as I figure these must both be valid for Character Rigging with APEX. I am using Houdini 20.5.
I'm seeing a behavior I wasn't expecting when using the "APEX Autorig Component" SOP with "Component Source" set to "smoothik", and I can't figure out what I'm doing wrong.
When I input the joints into the Parameters under the "Driven" tab by explicitly specifying the names of each one - everything works fine.
However, when I use the tag syntax - the ik handles are created at the scene origin instead of on the hand joints, none of the new arm controls appear to drive any of the joints.
The APEX graphs from each method obviously look totally different. It looks to me like things aren't parented properly, but I'm still new to APEX so I'm not sure.
I've triple-checked my tags, which look like so:
I've attached a .hiplc so hopefully someone can spot whatever mistake it is that I'm making.
Many thanks,
A