Sudden sharp adjustment in the bond market: What happened?

On October 30, the ultra-long end of the government bond futures market weakened first, with the 30-year main contract closing down 0.73%, the largest single-day decline since March 9; cash bonds weakened in tandem, with the yield on the ultra-long special government bond "26 Ultra-Long Special Government Bond 04" rising 3 basis points to 2.083%. Credit risk news about a certain local state-owned enterprise circulated in the market, and institutions holding positions sold off in advance out of risk-control considerations, which also made the market "bend over," with panic spilling over from LGFV bonds to the entire bond market, and even interest rate bonds were not spared.