1 | initial version |
Without checking all the commits on the TCP dissector, I would assume there was a code change in 4.2.x that changed this behavior and it has been reverted or at least fixed so that the "TCP ACKed unseen segment" are back for ACKs that ACK segments that Wireshark did not see.
Did you try 4.2.7, it should have been fixed in the 4.2.x release as well, if not, could you open an issue on our gitlab wiki so it can be fixed in the next release of 4.2.x?