Google Nest Topaz 2.7, Topaz 2.9

SaferProducts.gov consumer incident report 20211108-6853C-2147358868. Severity: Incident, No Injury. Product: Google Nest Topaz 2.7, Topaz 2.9 (Google Nest Protect models Topaz-2.7 and Topaz 2.9. Software version 3.4rc6 Smoke alarm). Incident: Google Nest Protect smoke detectors are not sounding the alarm at every smoke detector when smoke is detected. Google's specifications, as well as fire/building codes in California and other states, require smoke detectors to sound an alarm at every detector when any detector senses smoke. This is a serious safety hazard. This functionality is required to ensure that everyone in a house is alerted when a fire is detected somewhere in the building. Details: My home has 7 Nest Protect smoke detectors. I have tested the system using a blown out match as well as canned smoke at multiple different detectors. In each case, the individual Protect detected the smoke and sounded its alarm (an actual "emergency" alarm--not a "heads up"). In addition, I receive an "Emergency: There is smoke" notification on my phone. However, the alarm did not sound on any of the other 6 Nest Protects. Nest's built-in test shows that all 7 Protects are correctly interconnected and operating properly. I have reported this issue to Google's support on 3 separate occasions with no response: 1) On 10/27/2021, I reported this to Google's chat support. After escalation, Google told me they do not recommend testing the Nest Protect this way and disconnected. 2) On 10/27/2021, I reported this to Google's phone support. The support rep agreed this was an issue, escalated the incident to the Nest safety team and told me I should hear back within 24 hours. I have not yet had a response. 3) On October 31, I posted this incident on Google's Nest Community. The Product Expert there agreed this was an issue and esca