Bruce Yuanyue Bi/Getty ImagesTraders have pulled $5.3 billion from BlackRock's iShares 20+ Year Treasury Bond ETF this month, on track for an all-time high.At the same time, equity sentiment has surged as investors expect another year of strong returns for the S&P 500.Weakening bond sentiment could prove a contrarian indicator heading into 2025, Rosenberg Research says.Investors aren't feeling good about the bond market heading into the new year.