Strange phenomenon seen in the tcpdump

If you are using vCMP and doing the tcpdump from the quest then maybe this is the virtual connection from the quest to host as this virtual interfaces are named 0.x  https://my.f5.com/manage/s/article/K03740927  

Other than that "tmsh show /net interface -hidden" may show it (iSeries have internal interfaces to the bc switch inside F5) if it is not vCMP but the format seems like vCMP.

example:

Interface flapping on internal, non-physical interface

Better as it was already mentioned to focus on the interface or vlan that you want to capture traffic as in F5 the vlan name can also be used as an interface 😉