I have multiple sets of same numbered daily mixes, also don't have endless Daily Mixes but have "former" Daily Mixes that remain endless
(first of all, I had no idea how to post to Help -> Ongoing Issues. There was no [start a topic] button over there, so I'm posting wherever this ends up in)
Before I installed Windows 10 on my desktop a week ago (which already had Spotify installed) everything was fine: Daily Mixes were endless, what genres each list represented were always consistent for over 10 months. But now in the Made For You - Daily Mixes section, all those mixes are just playlists, not endless, and inconsistend everyday, the genres keep switching over from 1 to 5 and then something else. The only way I can access my former Daily Mixes (marked red), are form the Recently Played list. And in the screenshot down below, it clearly displays that the new Daily Mixes (marked blue) have become playlists, with a certain set of tracks and length. The older Daily Mixes that still remain are still endless, and display "more songs load as you listen" below the page.
My only guess as to how to reproduce this would be: Have a spotify that's mainly used on Android or web browser with consistend and endless Daily Mixes. Then suddenly after half years login from a Windows' Spotify app.
As much as I'm aware, the desktop app is up to date, but is the Microsoft Store version that came preinstalled in my new Windows 10.