We had a similar problem with our B 321 with Profurl,We were preparing to remove sails and take mast down for winter.Un rolled jib released halyard, sail would not lower ,tried re tensioning halyard no luck.Took mast down with sail stilled rolled.
Problem was halyard had caught on top of guard at top of furler.
Suspected cause--when we went to lower sail wind at the dock was extreme (we were facing into wind) suspected the floging sail caused the problem.We have not had the problem since (4 years) Just make sure we lower sail in calm conditions.