Binary dump not respecting ulimit

OE 10.2B and OE 11.3.1 + Linux

According to the KB, if the binary dump hits a user's ulimit, it should switch to the next file (.bd2, .bd3...).  This is no longer the case on Linux.  When I dump, the setuid root kicks in and the file size is unlimited, regardless of the userid.  If I remove the setuid bit, the dump fails with :

File size limit exceeded. (3697)

Is this a bug ?

Paul