There are two in the Cincinnati area w/Echelon meters and 2-3 others where the reports are indirect (email to Jeff Volp) and with different meters (IIRC).
And I'm not dismissing any of them - it's just extremely difficult to identify anything that all have in common. So far, I cannot find anything that definitively explains anything the various smart meters all have that might affect X-10 and UPB but not Insteon.
My favorite candidates are spikes and/or brownouts (i.e. momentary voltage dips) which are a known issue for X-10. Spikes could be a problem for UPB but I've never heard of them being a problem for Insteon. Some or all of the meters output pulses meant for third-party energy monitoring devices but how these are output differs - flashing LED, serial output, ZigBee, pulsed relay... None appear to directly put pulses on the power-line but some of the relays are connected to Neutral which might cause spikes/dips when the relay coil de-energizes (inductive kickback). Since the frequency of the pulses is tied to total energy use, that could account for the apparent randomness.
And, the fact that some of the victims are long-time X-10 users might also be meaningful as some of the vulnerabilities may have been addressed in later designs (it was just sloppy design).
I believe Jeff favors a different candidate.
Some meters send data over the powerline to an aggregator at the transformer. This might be leaking into the household wiring but, again, the details/mechanism are a mystery.