从数据库中读取NVARCHAR后，TClientDataset Widestring字段的大小会加倍

I'm converting one of our Delphi 7 projects to Delphi X3 because we want to support Unicode. We're using MS SQL Server 2008/R2 as our database server. After changing some database fields from VARCHAR to NVARCHAR (and the fields in the accompanying ClientDatasets to ftWideString), random crashes started to occur. While debugging I noticed some unexpected behaviour by the TClientDataset/DbExpress:I'm converting one of our Delphi 7 projects to