/camp and log back in, or zone is generally the fastest way, assuming you zone reasonably fast. About 1-2 mins for /camp. At least you don't have to wait 5 mins to Unsuspend the merc. If your zone time is really slow it may take more than the 5 min unsuspend time, and that would be the quickest then.
Those are the only 3 ways I recall that fix it for sure. And, zoning I've read doesn't always fix it as sometimes it takes multiple zones, but it has always worked for me on zone out and back in or /camp.
Yther Ore.