Observers Sends False Pulses

I'm unable to reproduce this.

the problem lies that when the tree is blocked from growing and try to apply bone meal sometimes it sends false pulses even if the block in front hasn't been updated. This bug is possible in every version that has Observers

even without bonemeal it sends false signals i sped up the tickspeed so you can see 

Saplings will grow to stage 1 before becoming fully grown.  I think that is what the observer is detecting.  Try pressing F3 and looking at the sapling that the observer is looking at, and looking at the "targeted block data" on the right.

If you're trying to detect the tree growing, try moving the observer up by 1 so that it only detects when the wood replaces the air.

Hmmmm i done what u asked but it's not that it goes off when it feels like it also moving it up one would take more bonemeal to grow it.

And the whole stage 1 thing is quite wierd if you speed it up it tells you it's not in stage one but when you leave and enter the same world it tells you it's stage 1 (i'm guessing it's the reloading that makes it acknowledge it because when i reloaded the chunk it also change back to stage 1)

I'm unable to reproduce this, both in 1.14.4 and in 1.15-pre2. The observer only triggers twice, once for the sapling growing up and a second time for the tree actually growing.