I want to replace the new: 
crimson_door_top.png
and
crimson_door_lower.png
I placed new textures into the pack but the door stays the same.
Then i tried using other door textures:
I renamed the same two textures to: door_acacia_lower and door_acacia_upper
And they work!

To Replicate:
1. Make new texture for: crimson_door_top.png and crimson_door_lower.png
2. Activate the textures for the world

To see why its a Bug:
1. Try the new textures with: door_acacia_lower and door_acacia_upper or other older doors

I provided both Versions as upload.