We've tried swapping weapons, input method, even people, only level 7 seems to not work, we can easily go through the start and 6 levels. Only level 7 appears to just not work, we tried inputting it one by one, all at once, nothing works. We get a lot of problems like this, sleeper nodes on mars for example, even after going through 300 nodes after the "fix" we still seem to be getting redundant nodes (thus we can't get the triumph and the emblem for them) Can I also mention that lack of support ticket system is annoying? I understand that you would get a lot of questions that are already answered in FAQ but it impacts the players that really need help.
ValiantLem explains the problem perfectly. We had been having the same problem for a few days. The Fish hitbox is way outside of what it should be. https://www.youtube.com/watch?v=alMe09ZtY0U Watch this video by SneakyBeaver and go to 10:27. He shows you exactly where the hitbox is for the Fish. Make sure to get a hitmarker on the Fish to confirm that it went through. Good luck!