Either there are loads, charge source failing, wiring/connection issues, or your bank has died prematurely.
Are you assuming your Link is accurate as to the bank being full?
Verify everything with DMM, clamp ammeter. Starting with charge algorithm, do amps fall to 2-3% of bank AH before going to float?
Do you see any load amps flowing out?
Isolate all loads for a couple cycles.
If you conclude the bank's dead, do a 20-hour load test on shore before scrapping.