Sometimes Homey is very very slow to move things over and the other way too - its slow to discover matter devices.
In my experience, delete it as a favourite, shut the apps down and try again.
Alexa isnt the best either and it can duplicate and lose devices / routines easily. Ive tried many times to discover devices and got nothing, only to find they auto added. Have a search around and check for typos!
Unless something new has broken recently, its been a pretty slow process all along.
so is this an Alexa issue or a Homey issue?
I made a flow a favorite and ran discover devices only to have alexa not find any new flows. So I’m in the middle of making an Alexa routine but I have to stop and remember to keep trying until Alexa sees the new flows and then finally make the Alexa routine….