I use link but on the 1800. I share a usb stick between the two players. I don’t use layers.
I’m connected to channel 2 and 3.
I haven’t experienced any link dropping issues.
My issue includes on a 2TB Fat32 mechanical drive rather than a thumb drive, but some part of what I experienced InMusic confirmed as a real firmware issue, so it’s not just failing hardware. I use layers and alternate my decks continuously. I play from 1 to 4, then 2, then 3, then repeat, in case I need to keep two tracks running at once while cuing up another. I spread the wear on the players and the mixer. If, however, we’re having the same issue and it’s not as simple as a general hardware ethernet port issue or even an initialization issue of the software protocols for the link that myself and InMusic seems to have assumed, then it’s almost like in your situation using certain ports exclusively for an extended time is increasing the chances of those possibly eventually failing. I’m plugged into different ports, yet I still have temporary issues that restarting the linked player eventually resolves. There’s also the option to use the link directly between the two units bypassing the mixer if 1 and 4 begin acting up for you. If you start having issues again on 1 and 4, and then direct link has issues, then definitely the problem’s not specific to certain ports. I can’t help but think if my issue is resolved with restarting, yours is not, and yours is further helped by changing which ports you’re using, then you might have a different issue than this supposed firmware link glitch.