upgraded 9.1-RELEASE - Snort TCP 3 way handshake error

[freebuser]

Hi I have upgraded my server from 9.0-RELEASE to 9.1-RELEASE (releng/9.1) via buildworld.

And now I receive this log in snort:

snort[26064]: [129:20:1] TCP session without 3-way handshake [Classification: Potentially Bad Traffic] [Priority: 2] {TCP}

Anyone have any idea?

Thanks with regards,
freebuser