Sorry about dredging this up again, but I just had it happen to me again. This time I managed to snag some screenshots in the process. The flight was from Brisbane (YBBN) to Auckland (NZAA), using a Project Airbus A320 with the FSX A321 panel available from the ISG Panel Retrofits page.
When I loaded the route into the FMS (SCOTT A464 PAPTI), everything was fine. The course line was displayed normally as I expected it to be (I did not get a screenshot of that unfortunately, since I was not expecting trouble at that point). However, when I selected the SID and departure runway (SCOTT 5 and runway 01), the course line disappeared for a moment, then reappeared showing the end of the course, with the label for NZAA displayed upside down (
http://i22.photobucket.com/albums/b315/ ... /FS027.jpg). The course line disappeared again shortly after I started to taxi and remained invisible for most of the climb, though the LNAV function worked properly, and the calculated TOC indicator was displayed (
http://i22.photobucket.com/albums/b315/ ... /FS028.jpg,
http://i22.photobucket.com/albums/b315/ ... /FS029.jpg). The course line reappeared shortly before reaching cruise altitude (
http://i22.photobucket.com/albums/b315/ ... /FS032.jpg) and everything was fine during cruise.
Shortly before reaching PAPTI, I selected the STAR and arrival runway in the FMS (BASIV 5A and runway 23L). Initially there was no change to the displayed course line. However, shortly after starting my descent, the course line again disappeared (
http://i22.photobucket.com/albums/b315/ ... /FS033.jpg). As I continued along the STAR, the course line eventually appeared on the display, but it was shown as if it were coming from the opposite direction (
http://i22.photobucket.com/albums/b315/ ... /FS034.jpg,
http://i22.photobucket.com/albums/b315/ ... /FS035.jpg) and with the waypoint names angled instead of horizontal. As I was on downwind, the course line was displayed correctly, but offset about 10 nm to the right of where it should have been (
http://i22.photobucket.com/albums/b315/ ... /FS036.jpg). Once I was clear of the runway and taxiing towards the terminal, I checked the display again and now the course line was completely accurate (
http://i22.photobucket.com/albums/b315/ ... /FS037.jpg).
For the past couple months, most of my flying has been in a 737 and E190, using panels from the ISG Panel Retrofit page, and I did not have any problems at all. This was my first flight back in an A320, and the problem popped up again (I believe all of the previous flights when I experienced this problem were using this same A321 panel). It isn't critical, because it appears to be nothing more than a display issue. The LNAV function works fine, and follows the course even if it is not displayed, or if it is displayed incorrectly.
*Edit* Oh, and just in case there are any questions, this is not an April Fool's joke.