Hmmmm, what is the data type of the particular column in the database?

Sometimes users can put strange characters into varchars and nvarchars like tabs and carriage returns so you could try doing a trim in your query - LTRIM(RTRIM(your column)) to get rid of certain undesirables. Or there is a more comprehensive function here.

I found this thread which describes a similar problem and may be of assistance.

Does it just occur when you try to export from SSDT (formerly BIDS :rolleyes:) or does it happen when you have deployed the report?