Best answer by UKMedia
To be specific, do you have three Sonos One's (With Alexa) or three Play:1's (Without Alexa)?
Can you please check that all device and group names are unique in the Alexa App>Smart Home>Devices & >Groups
Can you then open the PC version of the Alexa App (https://alexa.amazon.co.uk or https://alexa.amazon.com) and select Smart Home>Devices> and then scroll to the bottom of the list and select 'Forget All' followed by 'Discover'. WARNING: This will delete ALL actions in ALL Alexa Routines...