Why does Alexa answer questions I didn't ask or prompt?

Question

I just got a new Echo Dot and it works normally when prompted. However, three times today she said without prompting, "I'm sorry, I can't find the answer to that question." I checked on the app and three questions I did not ask are logged, but they are a jumble of words that make no sense. The only thing I can think of is somehow Alexa is picking up parts of conversations from the TV in the same room. How that could happen without prompting, I have no idea. If someone has an answer, please share.

Examples of un-asked questions:

• "You are you siri"
• "Give you France medication is working for you ask her gastroenterologist about a tibia."

Wake word: Alexa.

Answer 1

I can't speak for Alexa, but google on my phone frequently seems to mis-trigger, thinking it's heard the 'OK Google' when there is just noise. It doesn't seem to happen when the environment is quiet, but sometimes when I'm driving, or of people are moving around, it will trigger.

Related article (in German) describing how a synthetic fingerprint can match 2/3 patterns used for unlocking phones. A more general example of false correlation (and how non-natural data may show false fits more easily than data constrained by it's anticipated source).

This is a good example of why it is important to validate sensor data before using it. Your CCTV can (often) be blinded by a laser, or your entropy source flatlined by EMC interference. Both of these can easily be detected (and are equivalent to the sensor failing open/closed-circuit) but wouldn't necessarily be identified as important to test for when you're developing an IoT device.