Add some kind of "anti-trigger" to ignore the wake word in audio.
Allow the adding of some kind of "anti-trigger" that will stop Alexa waking itself when the invocation word is mentioned in a podcast, or SSML audio. And/or, allow a flag that will reduce sensitivity to the wake-word during a particular piece of audio, using the mic array to detect whether the wake word was generated internally or externally.
I know that there is an unofficial theory that self-invocation can be lessened by boosting / cutting certain frequencies around the actual wake-word, but this isn't always practical where third-party audio is involved.
Richard A Walton commented
Ths happens a LOT during Audible Books, a part of Amazon. In recent times it has reacted to 'Alexis', 'Computer', 'Echo', and everyone's favorite, 'Amazon'. Example: "Dungeon Madness" which has Amazons, "Gone Rogue" who has a character named "Alexis", and I even got to hear "Echo" once, when they were talking about a repeated sound.