Regionserver attempting to open reassigned region but master ignoring, thinks region is still closing

Write heavy load (splitting) causes some regionservers to report overloading to the master. Master closes the regions on the affected regionservers and reassigns them. Regionserver(s) that get new assignments attempt to open the region, but master ingores the open request because "region is closing".

More information forthcoming once I have a chance to analyze the logs.