Glacian trap doors will always be placed east-west axis no matter where it is facing ( north , east , west , south )
But this is only when it is not activated
Here are some screenshots :

• a trap door facing south
  
• a trap door facing east , u can see that they are on the same axis
  
• and now when I activated the trapdoor , for some reason the axis changed
  

This might be a minecraft issue; I'll check it out but I don't think I can do anything about it.