[0.18.8] Incorrect ghost track rotation when rotating manually

[TPReal]

Steps to reproduce:
1. Place a track segment.
2. Click the arrow to extend the track, and hold down the modifier to place ghost track.
3. Move the cursor away from the track, let's say down and to the right, so that a longer segment of ghost track is displayed (still not placed). Now the unplaced ghost track arrives at the cursor from some direction, probably from NW.
4. Still holding the ghost modifier, and not moving the cursor, now press the "rotate building" key, e.g. the one that rotates CCW.
Expected behaviour: The track should now arrive at the same point, from the direction W.
Actual behaviour: The track now arrives at the cursor point from a seemingly random direction, e.g. NE.

If the rotation key is then pressed again, it works as expected: each press rotates the arrival direction by 45 degrees. There is only a problem on the first press, which sets the arrival direction to something surprising, instead of rotating the currently computed (and displayed) rotation direction by 45 degrees.

Because of this, I need to press the rotation multiple times to find the correct one, instead of just once if I just wanted to adjust the direction by 45 degrees. It's especially annoying in tight spaces, where the track rotated to the random position cannot fit at all, because it is then not displayed at all, and I don't even know what is the current direction, I just need to repeatedly press the rotation key until the ghost shows up again.