pg_tables query issue

Hi List;

I've found that if I run this select (below) I get a table returned
named 'dma' een though I specified like 'dm_%' :


select tablename from pg_tables where tablename like 'dm_%';


           tablename
------------------------------
  dm_service_provider_dim
  dma


Am I missing something or is this a bug ?

Thanks in advance..

/Kevin