About protection circuit

[tungbuivn]

Here is protection for the hotbed temp

if for some reason, the 24v going to pin 1 of j26, then every circuit is protected by the zenner D46-1, it will make sure voltage is 3.3v, but the power of zenner only 50mW, and the massive current from 24v will destroy zenner D46-1, so the circuit become unprotected and 24v will replace power source 3.3v, can it burn our board ?