Results of query with substr command (1 reply)

I'm having problems whenever my query contains the 'substr' command. In the results window the cells in the respective column contain only 'BLOB' and when I export the results, they are empty.
Any suggestions how to deal with this? Funnily enough, the problem did not exist in an earlier version of Workbench I was using (5.2.16 beta)
Thanks!