I think I have mentioned this before, but it is annoying me in my current game so I am reporting it again.
The cultural influence borders do not accurately reflect the influence of the civs in the enclosed cells. The first screen snapshot below shows a border between my civ (turquoise) and the Luxar Dominion (white). The jagged line is obviously incorrect but, more importantly, the second screen snapshot shows our relative influence for a cell that is well inside area for the Luxar Dominion and it shows that my influence is double that of the Luxar Dominion. In fact, my civ has more influence than the Luxar Dominion in ALL of the cells on this side of the gate.
What is very interesting about this is that this is occurring at a subspace gate. The third and fourth screen snapshots below show the gate at the other end of the subspace stream where the exact opposite problem is occurring - the borders show that my civ has cultural influence dominance for a number of cells, but some of the cells within my border have a higher influence by the Luxar Dominion.
I believe you need to put a high priority on fixing the logic that controls drawing the cultural influence border since it is visually supposed to show how far a civ's influence extends, but it is easy to see that it is wrong by just hovering over a cell.