it looks like it has come out of the threads and the twist of the joint is holding it in.

can you get access to the threaded end and confirm if it's still in there or not?

if it is free at one end thn you can get a slide hammer and fix to the head of the bolt and pull it out.

might help to lever the bushing casing so it's not putting as much pressure on the bolt.

i've used a lever under the bolt head before and then just put the gun on there untill it winds it's way out.

if it's under tention then it might kill the bolt's threads.

try to release the pressure by moving the bushing with a lever.

if it's stuck in the threads then it's harder.

you could cut the bolt with a cutting disc on a grinder, then you'd have to drill th renainder of the bolt of the thread and tap the last bit out.

or maybe the nut part has brokn off the mounting? if so just clamp it and carry on undoing the bolt.

good luck