When a ship is moving in the galaxy, it has a start point and an end point (obviously). No matter where these two points are, it is possible to draw a straight line from the start point to the end point. This line will ignore all impassible objects and all areas that cost more or less movement points than the basic 1 per tile.
When the game uses the code that calculates the path the ship needs to follow to get from the start to the end, the code takes into consideration the impassible objects and areas that cost extra movement points as well as those that cost less than 1 per tile to calculate the most efficient path.
When the game code that moves the ship takes over, many times it ignores the calculated path and tries to take the straight line to the destination. It seems like the longer the distance between the start and end the more likely the calculated path will be ignored. I have seen this many times before Retribution (and reported it several times), so it has nothing to do with the hyperlanes. With retribution it is more obvious when the a ship takes a "shortcut" that takes more movement points instead of the longer path, in number of tiles, that takes fewer movement points.
In my current game with the 3.7 opt-in I was seeing this, so I took a screen shot each turn for 3 turns showing the calculated path and the location of the ship each turn. I then combined them into this picture showing the calculated paths and ship location for those turns.
The path the ship is taking is almost straight to its destination, but it won't take it all the way because there is a black hole in the straight path.
I also recorded a short video that shows the calculated path and actual movement for 1 turn. You can download it here.
Since the devs have a much easier time finding the cause of the problem if a save is provided, here is one at the end of the first turn in this sequence. As shown in the above picture, the ship is just south of the home star system. Just click TURN to get the ship to move in a direction that is almost at a right angle to the calculated path. This can be continued for many more turns, if necessary. I'm using several of my mods in this game, but I don't think that matters.
I hope this helps find the cause so it can be fixed.