I checked the data and the railings are currently set correctly (they can be learned from skill leveling or schemes). If they were incorrectly set to auto-learn at some point during the past few weeks, I can't tell right now.
If you are a player that auto-learned railing schemes, please contact me with information on when you learned the railing schemes.
Regarding parts that were once valid but are now invalid (red), this is most likely due to changed with 8x8 trusses and the addition of beams. Beams are now required to support walls within trusses. If there is a specific situation where you think that parts should be valid but currently are not valid, I need an exact location on the Test Server to check this. I can't run proper tests on the Main Servers because I can only debug code while running and restarting the game on the Test Server or my Local Server.
Thanks!