mail(1) core dump

[jamie%kontrol.kode5.net@localhost (Jamie Paul Griffin)]

I've come across a problem with mail(1) crashing whilst viewing in thread mode; 
specifically, when i've used 'expose' and then incorporate new mail either 
using the inc command or when autoinc is set in the mailrc file.

This is the error output:

assertion "omsgCount == 0 || message->m_plink == NULL" failed: file 
"/usr/src/usr.bin/mail/thread.c", line 494, function "thread_fix_new_links"

could this be a bug?

        jamie.