2x2 spruce trees randomly fail to spawn despite meeting all valid spawning conditions. Tested this in creative and survival, and some of them will just get stuck on age 1 and never grow. Seems to happen more often when two are planted near each other, one grows first and in a manner that would prevent the second from growing, the second one hits age 1 and fails to grow because of the obstruction, and then even once the obstruction is cleared that second one is now incapable of growing. Originally saw this in survival so I tested this in a creative world clearing a 20 block radius and applying over 1000 bone meal and still no growth.