When replacing observer by setblock or fill, its output direction doesn't change

Steps to reproduce:
Create a new world and place any solid block and stand on there.

1. First way
   1-1. Place a observer using /setblock ~~-1 ~ observer ["minecraft:facing_direction"="west"] or just place a observer but facing west.
   1-2. Place a block that updates using redstone (like redstone dust) in front of (observer input direction) a observer.
   1-3. Place a observer using /setblock ~~-1 ~ observer ["minecraft:facing_direction"="east"].
   1-4. Place a block that updates using redstone (like redstone dust) in front of (observer input direction) a observer.
2. Second way
   2-1. Place a observer using /setblock ~~-1 ~ observer ["minecraft:facing_direction"="east"] or just place a observer but facing east.
   2-2. Place a block that updates using redstone (like redstone dust) in front of (observer input direction) a observer.
   2-3. Place a observer using /setblock ~~-1 ~ observer ["minecraft:facing_direction"="north"].
   2-4. Place a block that updates using redstone (like redstone dust) in front of (observer input direction) a observer.

Related to MCPE-149124

Video that reproducing this bug: https://drive.google.com/file/d/1PJ_iPq2nHgSTSrfRpV5sxXCRfdhN8PQw/view?usp=sharing