I wasn't sure where to put bug reports, but I am continuously seeing a bug with the grappling hook, where it will not load the weapon correctly. At that point the following things happen:
Riders arm stretched out with cross hairs, but no weapon shown and no hook will shoot. You can't change weapons from the grappling hook. When you fall and get back on the bike, the bike jitters and can't drive unless you reset back to track. Resetting back to track will not reset this bug (quitting is the only solution)
It has happened on both roof top and ground maps. I have seen it happen when I have at least 2 guns, and the last time it happened, it was a shotgun, uzi, C4, grappling hook.