Yahoo is wrong. I suspect they had the old bond fund listed in that sector before the merger and did not update it after the change. The top holdings in a debt fund would not be Exxon, General Electric, Citibank, etc.
Actually, Yahoo is correct in terms of showing it in the debt portion. It gets that info from other sources. They may have similar holdings but the swings in the market sectors will drive the stock price. So if debt funds dive then CRF will dive. It is one of the drawbacks of sector trading.