If a region is assigned before log splitting is done by the server shutdown handler, the edits belonging to this region in the hlogs of the dead server will be lost.
Generally this is not an issue if users don't assign/unassign a region from hbase shell or via hbase admin. These commands are marked for experts only in the hbase shell help too. However, chaos monkey doesn't care.
If we can prevent from assigning such regions in a bad time, it would make things a little safer.