oh i tried this too a couple times, usally when somebody kicks my or when a cav bumps me when i release the bolt.
but i somehow always get it to work again, i thought it was an lag issue with in my game, but since u guys have tried it too, it's probably an bug or on purpose.
"Damn crossbow, arrggh" Bjarky starts hitting the jammed thing, aims for a while, cancels aim, changes weapon, goes back too his crossbow, aims for while, cancels aim, tryes to shoot, nothing happens... after a couple forths and backs Bjarky is able to reload, aims, shoots: PEW "Muahaha it works again, damn crappy technology!!" Bjarky tries to reload again, but something weird happens: "What the crossbow still is loaded?!"
After getting it to work again, I've experienced that i get back the lost bump shot, without reload, on top of the next shot = 2x shots on 1 reload o_O
thats why i always thought i had a lag problem...