Suricata

Hi all,
I have been experiencing some weird behavior in Suricata with regards to fragmented IP packets, and tunnels. It seems that when Suricata defrags it sets the 'defrag parent' up as a tunnel, which ends up making Suricata output in the alert that it detected a tunnel. These tunnels however have a depth of 0 and the root src and dst ip are equivalent to the tunnel's src and dst ip.
Is this intended behavior? Am I misunderstanding something? Code surrounding this is here I believe https://github.com/OISF/suricata/blob/master/src/defrag.c#L884