Thanks for the reply, ArKay99.
Repairing permissions: of course I did that.
Ethernet: unchecked, Eucon: checked. As in my initial post, the controllers are connected via an Ethernet switch to Port 1. Connection is just fine. In case I run into connectivity issues, I might want to try your approach. Thanks for the idea.
I have Eucon 2.7.1 and PT 10.3.5.223. Install/uninstall: I have a clean OSX clone on an ext. HD - I just cloned it back and installed PT, then Eucon. Now that Eucon 3.0 is out I will give it a try.
Weird issue with these soft button speaker pops - starts to sound like a hardware issue with the Transport, no?