I would think that it is possible for a device configured to log to a syslog server, with the server address set to 0.0.0.0 could, theoretically, arp to find the MAC address to match - however this would indicate a flaw in the firmware/software of that device, since 0.0.0.0 should never be considered a local address, and it should then attempt to send the log data to the default gateway.
To my way of thought, it should also not be possible to enable logging without setting a valid ip address for the log server.
I want to suggest another possibility - do you have a dfault gateway configured on those switches? Or is that also set for 0.0.0.0 - this might be the reason that the error message points back to the switch address.