FreeBSD doesn't stop the reconfig timer for a ssn/tsn reset request, if the response field is 0xffff. The response is not a valid result code but RFC 6525 said that at first an implementation should stop the reconfig timer regardless of which result is in the response parameter. If the result code is only 6 the reconfig time should be started again.
see tests
https://github.com/nplab/RFC6525_Testsuite/blob/master/implementation_tests/sctp-sr-i-pv/sctp-sr-i-pv-i-6-3.pkt