cannot generate corefiles

I hope someone can help with this.  A customer is unable to generate core dumps on a specific program, but other programs are not affected.  This problem prevents debugging of service outages resulting from unexpected termination of the process.

When the issue was originally reported, it was found that per-process core dumps were disabled.  However, even after enabling the per-process core dump, the issue is not resolved.

Here is the output of coreadm:
             global core file pattern:  /data/cores/%f.%n.%p.%t.core
             global core file content: default
                   init core file pattern:  core
                   init core file content: default
                    global core dumps: enabled