piston power supply problem

When I wanted to build my redstone I discovered that when I light up my piston as in the picture shown, it activates, so it's normal.

When I destroy the block that powers it, it always remains activated without powering up.

Is this normal?

 

 

to put it simply

when you have activated a sticky piston with a block of redstone, it will remain activated even though I had deactivated the power supply

 

allimented redstoneStickypiston Redstoneblock+stickypiston= bug

 

please share if you discover the same bug as me