I guess that what you call "v3" and "v5" correspond to the VMIDI3 and VMIDI5 virtual ports, right?
Do you mean Studio one to the Midi in of the al 88 (you said midi out) (one channel)
Actually not... When we are talking about MIDI In, it means physical MIDI In. If you send data from Logic to the AL-88 in order to be sent to an external synth, you are sending to an AL-88 MIDI Out. I know, it's quite confusing. And it is why we prefer to talk about "MIDI to CopperLan" and "CopperLan to MIDI" ports, because in can be MIDI In or MIDI Out depending on the nature of the port... the meaning of MIDI In/Out is not the same if the port is physical or virtual
The idea behind the test is to check if the AL-88 is losing the connection with Logic when at rest, and so shut down outgoing MIDI stream. So, please create a single channel connection from a virtual MIDI port used by Logic (ie VMIDI3) to the AL-88 MIDI Out, and then watch what is going out from the MIDI Out port using a USB MIDI adapter and MIDI-Ox. If you see some "all note off"/"all controller off", it means that the connection between AL-88 and the PC is not stable. It could be due to the Ethernet cable, the switch, or the AL-88 itself... In this case, please do the same test using a simple cable between the AL-88 and the PC (no switch). If the problem persists, the AL-88 is probably the cause.
On the other hand, if this test do not show any "all note off", here is another simple test that could be helpful to identify the cause:
- clear all CopperLan connections
- create a virtual MIDI cable between VMIDI3 and VMIDI1
- create another virtual MIDI cable between VMIDI5 and VMIDI2
- launch MIDI-Ox and monitor VMIDI1 and VMIDI2 input ports
- start your sequence and check the result.
You can copy-paste the result using right-click on the MIDI-Ox monitor window, so do not hesitate to post it here. MIDI-Ox displays time stamping information that could be interesting.