Perhaps the bolt is "naturally welded" to the metal sleeve in the bushing which sleeve has broken loose from the confines of the rubber...spins away and not able to go anywhere.

Who knows? Without images, Marcello, we are only guessing here.

My best "power of rust" adventure story was in trying to remove a brake rotor from a hub. I took the whole spindle assemby to a vocational school and used a 50,000 PSI press.

No joy. Finally just sledged and torched it off.

Cheers.