Hi,
did you got a chance to see through traffic of the switch ? is switch heavily loaded or excessive broadcasting ? would be worth to think from network prospective ...
LLT is performing as expected where after getting a disconnect, waited for 16 seconds & then declared the node as expired ... & later we can see the interface getting down & then up.
I would prefer to get the troubleshooting done from network (either switch port or switch settings, you have tried replacing the cable anyways) ... also you can match the interface settings at the OS layer to ensure nothing is suspicious over there (use ndd -get to see details & compare with other sites)
Also The VCS version you are using is very old & is EOL long back, would strongly recommend to upgrade to latest version... lots of bug fixes in latest versions ..
If you want to know more on LLT tools ... you can have a look at /opt/VRTSllt folder ...there are couple of tools like lltstat , llttest ... some of them would give very high level info though some would give detailed info which need to send out support ...
G