An idea about why stone pressure plates my be broken for players

This is a possible reason for pressure plates being broken.
Its possible that the carpet block using the same hit box and properties (other than being activated by player) have affected the pressure plates propeties file and can now not be activated as a result. Possible that you retextured the stone pressure plate and changed some files and propertiues and the pressure plate might be using some of those config files. Sorry if this is pointless thought i might try to help.