Mob skull blocks turn to skeleton skull blocks for a short time after placing

Mob skulls turn to skeleton skulls for a short time after placing.This bug only occours in survival mode.

Steps to reproduce:

1.place a skull of any mobs, like dragon heads and wither skeleton skulls.

2.just look at it.

Expected results:

the skull was placed and every thing is normal.

Observed results:

Mob skulls turn to skeleton skulls for a short time after placing.