Moving blocks take 1-2 redstone ticks to become movable

Please clarify what you mean. I would think moving blocks are already moving by definition.

So, when a piston starts to move a block, that block becomes a moving block, a piston extension takes 1 redstone tick, however there is a 50% chance that the moving block stays as a moving block for an extra 1 redstone tick than what is normally supposed to happen, i am not quite sure what causes this behavior

Could you upload a video or test world that shows how you are determining the inconsistency?

If I understand correctly, you're saying blocks moved by a piston are unable to be moved again after 2 gt 50% of the time?

Also, according to MCPE-15607 a piston extension takes more than one redstone tick.

I will create a video explaining the bug as soon as I can

In the contraption in the first picture, when it is activated, the second picture is what is supposed to happen, however, there is a 50% chance of the third picture occuring instead of the second picture.

I can confirm that the contraption in the picture is not deterministic:

However, there are many similar reports to this among the duplicates of MCPE-15793. It seems that both pistons and repeaters are inconsistent, and the pictured contraption uses both.

If you modify the contraption as below it is still non-deterministic, but due to random update order (see MCPE-16371).