Unreliable torq indication may indicate upcoming problem.
Surviving eight engine failures with engines like deHavillandGoblin, Allison C-18, Lycoming VO-540, General Electric CT58, PT6A-50 and PT6T-3, I may say the TQ indication in four of the occasions did show unreliable and erratic readings a few seconds before any other instrument or whistle went on.
These four failures were all related to serious internal engine oil problem.