Hi,
Yes, there probably is a loop and the device is flooded but have you tried to detach cables to test what happens then? Next step should be connecting cables one by one till the problem would be back. The you can trace the other end of cable and check your network.
Please try to read your own post as if you ware us. What would be your first thought?
Not enogh data but the question is too wide to answer?
What is the configuration?
Did thay guy do any additional test and what they results are?
What is the device connected to?
Lack of any network diagram?
It looks like a visit to a GP waiting for diagnose after describing a problem as "Doctor, I have cough. Is it possible that I'm very sick?"