After a couple of hours checking log files, software versions, update incompatibilities and a bunch of other nonsense, I found the culprit for my non-responsive home lighting automation was a dead power supply on the ethernet interface.

Foiled by the illuminated LED powered by the lighitng Bus itself, even though the controller had no DC power.

On the plus side, I got to verify all my internal docs, and got to throw away a couple of other dodgy power supplies from the junk box.