Last year I built the Octo node with a bare PCB I ordered from Mr. Radig as a hobby project.
So far it had various issues (dropouts in dmx signal etc) and I can now say I solved it. It turned out to be a fake/relabeled LM2596 chip from China. These chips are probably relabeled LM2576 which switch at a lower frequency and needs different capacitors/inductor. So as a warning to everyone who is building it by themselves; buy the original part. Hope someone has some use of this advice.