Most objects appear to break when hit with a melee attack on the user's client, but typically the objects remain unbroken on the server side (and thus on other clients).
To reproduce:
- Melee attack a breakable object like a pot sitting on the ground
- Note the breakable object breaks on your client.
- Attempt to move into the area previously occupied by the breakable object
- Note that the server does not allow you to occupy the empty space
- Fire a ranged weapon into the space where the breakable object existed pre-melee
- Note that the server now allows you to occupy the area previously occupied by the breakable object
This same behavior is observed for cash registers; other players will not see/hear the register open but the melee attacker does. Windows seem to break from melee just fine.