My pet theory is that this is the reason why Siri, Alexa and co. still are shit and haven't moved an inch forward since their inception.
I like to play "sleep music" through Alexa when I bring my kid to bed. For his mid day nap it all works perfectly. But in the evening when I say the same phrase that worked a few hours before the thing first plays "dance charts" and when I repeat myself it plays "german rap" - if I repeat myself again I'm back to "dance charts". This happens only in the evening. Next day for daytime nap it all works as expected.
Siri has the quirk that it won't turn off lights in the evening. During day it's all fine. In the evening "Siri turn off lights in the living room" ... nope. It fails. Every time. So I have to manually open the Home app and turn off the lights. (Turning on the lights via Siri works- turning off not).
Have fun debugging these, Apple and Amazon.