Hmmm, no. Cannot reproduce the issue. BTW, this thing is very much dead and has been so for quite some time. There are several forks, some of them even (claimed to be) IPv6 capable. If someone wants to work on getting one of those into FreeBSD ports, feel free.
http://sourceforge.net/projects/bandwidthdipv6/
https://github.com/neatbasis/bandwidthd