Weighted Pressure Plate read as Normal Pressure Plate

Put the summary of the bug you're having here

What I expected to happen was...:
there is new update "if we stand on weighted pressure plate it will work"

What actually happened was...:
when i check back on mojang there's no new update like that

Steps to Reproduce:
1. Put a Weighted pressure plate (iron or gold)
2. stand on it
3. then it will have clicked sound like normal pressure plate (wood or stone)