The significance of Dual-Stack and impact on TCP Flows !
It seems ISPs are performing Src PAT within the residential internet service provider space. I must have missed this I think. Notwithstanding, it's use I suspect is growing at an alarming rate, and has the potential to extend any associated investigation over an unexpected and extended period.
The symptoms I have observed is firewalls dropping flows with port 'reuse'
There's a few RFCs I see on google, here's one :
Not sure what the relevance is in regard to the subject Wireshark. If it has any then please elaorate on what your wireshark related question is.